diff --git a/src/module/rules/rule-element/item-alteration/alteration.ts b/src/module/rules/rule-element/item-alteration/alteration.ts
index 5fb1db76d34..5d717f5b4c9 100644
--- a/src/module/rules/rule-element/item-alteration/alteration.ts
+++ b/src/module/rules/rule-element/item-alteration/alteration.ts
@@ -152,7 +152,12 @@ class ItemAlteration extends foundry.abstract.DataModel<RuleElementPF2e, ItemAlt
                 const validator = ITEM_ALTERATION_VALIDATORS[this.property];
                 data.alteration.value = Number(data.alteration.value) || 0;
                 if (!validator.isValid(data)) return;
-                data.item.system.bulk.value = data.alteration.value;
+                const newValue = AELikeRuleElement.getNewValue(
+                    this.mode,
+                    data.item.system.bulk.value,
+                    data.alteration.value,
+                );
+                data.item.system.bulk.value = Math.round(Math.max(newValue, 0) * 10) / 10;
                 if (data.item instanceof foundry.abstract.DataModel) {
                     data.item.system.bulk = prepareBulkData(data.item);
                 }
diff --git a/src/module/rules/rule-element/item-alteration/schemas.ts b/src/module/rules/rule-element/item-alteration/schemas.ts
index 2fc2e05837b..95287b039ca 100644
--- a/src/module/rules/rule-element/item-alteration/schemas.ts
+++ b/src/module/rules/rule-element/item-alteration/schemas.ts
@@ -150,11 +150,15 @@ const ITEM_ALTERATION_VALIDATORS = {
     ),
     bulk: new ItemAlterationValidator({
         itemType: new fields.StringField({ required: true, choices: Array.from(PHYSICAL_ITEM_TYPES) }),
-        mode: new fields.StringField({ required: true, choices: ["override"] }),
-        value: new StrictNumberField<number, number, true, false, false>({
+        mode: new fields.StringField({
+            required: true,
+            choices: () => ["add", "downgrade", "multiply", "override", "remove", "subtract", "upgrade"],
+        }),
+        value: new StrictNumberField({
             required: true,
             nullable: false,
-            choices: [0, 0.1, ...Array.fromRange(100, 1)],
+            min: 0,
+            integer: false,
             initial: undefined,
         } as const),
     }),