diff --git a/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useY2Axis.ts b/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useY2Axis.ts
index 977729f25..c77725573 100644
--- a/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useY2Axis.ts
+++ b/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useY2Axis.ts
@@ -7,6 +7,7 @@ import {
   DEFAULT_CHART_CONFIG,
   DEFAULT_COLUMN_LABEL_FORMAT,
 } from '@buster/server-shared/metrics';
+import { fa } from '@faker-js/faker';
 import type {
   CartesianScaleTypeRegistry,
   Scale,
@@ -20,7 +21,7 @@ import type { BusterChartProps } from '../../../BusterChart.types';
 import { formatYAxisLabel, yAxisSimilar } from '../../../commonHelpers';
 import { useY2AxisTitle } from './axisHooks/useY2AxisTitle';
 
-export const DEFAULT_Y2_AXIS_COUNT = 7;
+export const DEFAULT_Y2_AXIS_COUNT = 9;
 
 export const useY2Axis = ({
   columnLabelFormats,
@@ -47,6 +48,7 @@ export const useY2Axis = ({
   const selectedAxis = selectedAxisProp as ComboChartAxis;
   const y2AxisKeys = selectedAxis.y2 || [];
   const yAxisMinValue = yAxis?.min;
+  const yAxisMaxValue = yAxis?.max;
 
   const y2AxisKeysString = useMemo(() => {
     return y2AxisKeys.join(',');
@@ -116,6 +118,7 @@ export const useY2Axis = ({
           includeBounds: true,
         },
         min: yAxisMinValue,
+        max: yAxisMaxValue,
         grid: {
           drawOnChartArea: false, // only want the grid lines for one axis to show up
         },
diff --git a/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useYTickValues.ts b/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useYTickValues.ts
index 3d3ee41b3..cf395fe44 100644
--- a/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useYTickValues.ts
+++ b/apps/web/src/components/ui/charts/BusterChartJS/hooks/useOptions/useYTickValues.ts
@@ -1,11 +1,14 @@
 /** biome-ignore-all lint/style/noNonNullAssertion: false positive */
+
+import round from 'lodash/round';
 import { useMemo } from 'react';
 import type { BusterChartProps } from '../../../BusterChart.types';
 
-const MIN_PERCENT_DIFFERENCE = 1.5;
+const MIN_PERCENT_DIFFERENCE = 2;
 const MAX_PERCENT_DIFFERENCE = 2;
 const MIN_OFFSET = 1.1;
 const MAX_OFFSET = 1.1;
+const PERCENTAGE_STEP = 5;
 
 export const useYTickValues = ({
   hasY2Axis,
@@ -25,23 +28,34 @@ export const useYTickValues = ({
   const shouldUseMinAndMaxValues = hasY2Axis && columnMetadata && selectedChartType === 'combo';
 
   const checkValues = useMemo(() => {
+    if (!shouldUseMinAndMaxValues) return [];
     return [...yAxisKeys, ...y2AxisKeys];
-  }, [yAxisKeys, y2AxisKeys]);
+  }, [yAxisKeys, y2AxisKeys, shouldUseMinAndMaxValues]);
+
+  const hasOnePercentageValue = useMemo(() => {
+    if (!shouldUseMinAndMaxValues) return false;
+    return checkValues.some((key) => {
+      const columnFormat = columnLabelFormats[key];
+      return columnFormat?.style === 'percent';
+    });
+  }, [checkValues, columnLabelFormats, shouldUseMinAndMaxValues]);
 
   const allYValuesArePercentage = useMemo(() => {
+    if (!shouldUseMinAndMaxValues) return false;
     return checkValues.every((key) => {
       const columnFormat = columnLabelFormats[key];
       return columnFormat?.style === 'percent';
     });
-  }, [checkValues, columnLabelFormats]);
+  }, [checkValues, columnLabelFormats, shouldUseMinAndMaxValues]);
 
   const columnMap = useMemo(() => {
-    if (!columnMetadata) return new Map();
+    if (!columnMetadata || !shouldUseMinAndMaxValues) return new Map();
     return new Map(columnMetadata.map((col) => [col.name, col]));
-  }, [columnMetadata]);
+  }, [columnMetadata, shouldUseMinAndMaxValues]);
 
   // Calculate min/max ranges for y-axis columns
   const yAxisRange = useMemo(() => {
+    if (!shouldUseMinAndMaxValues) return { min: Infinity, max: -Infinity };
     return yAxisKeys.reduce(
       (acc, key) => {
         const column = columnMap.get(key);
@@ -55,10 +69,11 @@ export const useYTickValues = ({
       },
       { min: Infinity, max: -Infinity }
     );
-  }, [yAxisKeys, columnMap]);
+  }, [yAxisKeys, columnMap, shouldUseMinAndMaxValues]);
 
   // Calculate min/max ranges for y2-axis columns
   const y2AxisRange = useMemo(() => {
+    if (!shouldUseMinAndMaxValues) return { min: Infinity, max: -Infinity };
     return y2AxisKeys.reduce(
       (acc, key) => {
         const column = columnMap.get(key);
@@ -72,7 +87,7 @@ export const useYTickValues = ({
       },
       { min: Infinity, max: -Infinity }
     );
-  }, [y2AxisKeys, columnMap]);
+  }, [y2AxisKeys, columnMap, shouldUseMinAndMaxValues]);
 
   const minTickValue: number | undefined = useMemo(() => {
     if (!shouldUseMinAndMaxValues) return undefined;
@@ -110,9 +125,16 @@ export const useYTickValues = ({
 
     // If both min and max values are similar, use the lowest min value
     if (minValuesAreSimilar && maxValuesAreSimilar) {
-      return Math.min(yAxisRange.min, y2AxisRange.min) * MIN_OFFSET;
+      if (hasOnePercentageValue) {
+        // If there's at least one percentage value, round the min to the nearest lower multiple of 5
+        const min = Math.min(yAxisRange.min, y2AxisRange.min) * MIN_OFFSET;
+        return Math.floor(min / PERCENTAGE_STEP) * PERCENTAGE_STEP;
+      }
+
+      return round(Math.min(yAxisRange.min, y2AxisRange.min) * MIN_OFFSET, 0);
     }
   }, [
+    hasOnePercentageValue,
     columnLabelFormats,
     yAxisRange,
     y2AxisRange,
@@ -122,7 +144,60 @@ export const useYTickValues = ({
     allYValuesArePercentage,
   ]);
 
-  const maxTickValue: number | undefined = undefined;
+  const maxTickValue: number | undefined = useMemo(() => {
+    if (!shouldUseMinAndMaxValues) return undefined;
+
+    // If all Y values are percentages, return the highest value
+    if (allYValuesArePercentage) {
+      const highestValue = checkValues.reduce((max, key) => {
+        const column = columnMap.get(key);
+        return Math.max(max, Number(column?.max_value ?? 0));
+      }, -Infinity);
+      if (highestValue === -Infinity) return undefined;
+      if (highestValue < 1) return 1;
+      return highestValue;
+    }
+
+    // Reset infinities if no valid data found
+    if (yAxisRange.min === Infinity) yAxisRange.min = 0;
+    if (yAxisRange.max === -Infinity) yAxisRange.max = 0;
+    if (y2AxisRange.min === Infinity) y2AxisRange.min = 0;
+    if (y2AxisRange.max === -Infinity) y2AxisRange.max = 0;
+
+    // Check if min values are within 150% of each other
+    const minValuesAreSimilar =
+      Math.abs(yAxisRange.min) > 0 && Math.abs(y2AxisRange.min) > 0
+        ? Math.max(yAxisRange.min, y2AxisRange.min) / Math.min(yAxisRange.min, y2AxisRange.min) <=
+          MIN_PERCENT_DIFFERENCE
+        : yAxisRange.min === y2AxisRange.min;
+
+    // Check if max values are within 200% of each other
+    const maxValuesAreSimilar =
+      Math.abs(yAxisRange.max) > 0 && Math.abs(y2AxisRange.max) > 0
+        ? Math.max(yAxisRange.max, y2AxisRange.max) / Math.min(yAxisRange.max, y2AxisRange.max) <=
+          MAX_PERCENT_DIFFERENCE
+        : yAxisRange.max === y2AxisRange.max;
+
+    // If both min and max values are similar, use the highest max value
+    if (minValuesAreSimilar && maxValuesAreSimilar) {
+      if (hasOnePercentageValue) {
+        // If there's at least one percentage value, round the max to the nearest higher multiple of 5
+        const max = Math.max(yAxisRange.max, y2AxisRange.max) * MAX_OFFSET;
+        return Math.ceil(max / PERCENTAGE_STEP) * PERCENTAGE_STEP;
+      }
+
+      return round(Math.max(yAxisRange.max, y2AxisRange.max) * MAX_OFFSET, 0);
+    }
+  }, [
+    hasOnePercentageValue,
+    columnLabelFormats,
+    yAxisRange,
+    y2AxisRange,
+    shouldUseMinAndMaxValues,
+    columnMap,
+    checkValues,
+    allYValuesArePercentage,
+  ]);
 
   return {
     minTickValue,