diff --git a/lib/subsetFonts.js b/lib/subsetFonts.js
index de69d9a3..c3e1e1fe 100644
--- a/lib/subsetFonts.js
+++ b/lib/subsetFonts.js
@@ -795,6 +795,19 @@ function warnAboutUnusedVariationAxes(
   const seenAxisValuesByFontUrlAndAxisName = new Map();
   const outOfBoundsAxesByFontUrl = new Map();
 
+  function noteUsedValue(fontUrl, axisName, axisValue) {
+    let seenAxes = seenAxisValuesByFontUrlAndAxisName.get(fontUrl);
+    if (!seenAxes) {
+      seenAxes = new Map();
+      seenAxisValuesByFontUrlAndAxisName.set(fontUrl, seenAxes);
+    }
+    if (seenAxes.has(axisName)) {
+      seenAxes.get(axisName).push(axisValue);
+    } else {
+      seenAxes.set(axisName, [axisValue]);
+    }
+  }
+
   for (const { fontUsages } of htmlOrSvgAssetTextsWithProps) {
     for (const {
       fontUrl,
@@ -805,83 +818,49 @@ function warnAboutUnusedVariationAxes(
       hasOutOfBoundsAnimationTimingFunction,
       props,
     } of fontUsages) {
-      let seenAxes = seenAxisValuesByFontUrlAndAxisName.get(fontUrl);
-      if (!seenAxes) {
-        seenAxes = new Map();
-        seenAxisValuesByFontUrlAndAxisName.set(fontUrl, seenAxes);
-      }
-      const seenItalValues = [];
       if (fontStyles.has('italic')) {
-        seenItalValues.push(1);
+        noteUsedValue(fontUrl, 'ital', 1);
       }
       // If any font-style value except italic is seen (including normal or oblique)
       // we're also utilizing value 0:
       if (fontStyles.size > fontStyles.has('italic') ? 1 : 0) {
-        seenItalValues.push(0);
+        noteUsedValue(fontUrl, 'ital', 0);
       }
-      if (seenItalValues.length > 0) {
-        if (seenAxes.has('ital')) {
-          seenAxes.get('ital').push(...seenItalValues);
-        } else {
-          seenAxes.set('ital', seenItalValues);
-        }
-      }
-      const seenSlntValues = [];
       if (fontStyles.has('oblique')) {
         // https://www.w3.org/TR/css-fonts-4/#font-style-prop
         // oblique <angle>?
         // [...] The lack of an <angle> represents 14deg.
-        seenSlntValues.push(14);
+        noteUsedValue(fontUrl, 'slnt', 14);
       }
       // If any font-style value except oblique is seen (including normal or italic)
       // we're also utilizing value 0:
       if (fontStyles.size > fontStyles.has('oblique') ? 1 : 0) {
-        seenSlntValues.push(0);
-      }
-      if (seenSlntValues.length > 0) {
-        if (seenAxes.has('slnt')) {
-          seenAxes.get('slnt').push(...seenSlntValues);
-        } else {
-          seenAxes.set('slnt', seenSlntValues);
-        }
+        noteUsedValue(fontUrl, 'slnt', 0);
       }
 
       const minMaxFontWeight = parseFontWeightRange(props['font-weight']);
-      const seenFontWeightValues = [];
       for (const fontWeight of fontWeights) {
-        seenFontWeightValues.push(_.clamp(fontWeight, ...minMaxFontWeight));
-      }
-      if (seenFontWeightValues.length > 0) {
-        if (seenAxes.has('wght')) {
-          seenAxes.get('wght').push(...seenFontWeightValues);
-        } else {
-          seenAxes.set('wght', seenFontWeightValues);
-        }
+        noteUsedValue(
+          fontUrl,
+          'wght',
+          _.clamp(fontWeight, ...minMaxFontWeight)
+        );
       }
 
       const minMaxFontStretch = parseFontStretchRange(props['font-stretch']);
-      const seenFontStretchValues = [];
       for (const fontStrech of fontStretches) {
-        seenFontStretchValues.push(_.clamp(fontStrech, ...minMaxFontStretch));
-      }
-      if (seenFontStretchValues.length > 0) {
-        if (seenAxes.has('wdth')) {
-          seenAxes.get('wdth').push(...seenFontStretchValues);
-        } else {
-          seenAxes.set('wdth', seenFontStretchValues);
-        }
+        noteUsedValue(
+          fontUrl,
+          'wdth',
+          _.clamp(fontStrech, ...minMaxFontStretch)
+        );
       }
 
       for (const fontVariationSettingsValue of fontVariationSettings) {
         for (const [axisName, axisValue] of parseFontVariationSettings(
           fontVariationSettingsValue
         )) {
-          const seenAxisValues = seenAxes.get(axisName);
-          if (seenAxisValues) {
-            seenAxisValues.push(axisValue);
-          } else {
-            seenAxes.set(axisName, [axisValue]);
-          }
+          noteUsedValue(fontUrl, axisName, axisValue);
           if (hasOutOfBoundsAnimationTimingFunction) {
             let outOfBoundsAxes = outOfBoundsAxesByFontUrl.get(fontUrl);
             if (!outOfBoundsAxes) {