diff --git a/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.md b/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.md
index f8f766c8bfa3..d814867d4117 100644
--- a/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.md
+++ b/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.md
@@ -72,11 +72,11 @@ Generated by [AVA](https://avajs.dev).
           compoundedInterest: {
             denominator: {
               brand: Object @Alleged: IST brand {},
-              value: 100000000000000000000n,
+              value: 857701650301172500n,
             },
             numerator: {
               brand: Object @Alleged: IST brand {},
-              value: 101967213114754098360n,
+              value: 874574469651359500n,
             },
           },
           interestRate: {
@@ -387,11 +387,11 @@ Generated by [AVA](https://avajs.dev).
             interest: {
               denominator: {
                 brand: Object @Alleged: IST brand {},
-                value: 100000000000000000000n,
+                value: 857701650301172500n,
               },
               numerator: {
                 brand: Object @Alleged: IST brand {},
-                value: 101967213114754098360n,
+                value: 874574469651359500n,
               },
             },
           },
@@ -413,11 +413,11 @@ Generated by [AVA](https://avajs.dev).
             interest: {
               denominator: {
                 brand: Object @Alleged: IST brand {},
-                value: 100000000000000000000n,
+                value: 857701650301172500n,
               },
               numerator: {
                 brand: Object @Alleged: IST brand {},
-                value: 101967213114754098360n,
+                value: 874574469651359500n,
               },
             },
           },
diff --git a/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.snap b/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.snap
index cd6de400d63f..a5a848519057 100644
Binary files a/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.snap and b/packages/inter-protocol/test/vaultFactory/snapshots/vaultFactory.test.js.snap differ
diff --git a/packages/inter-protocol/test/vaultFactory/vaultFactory.test.js b/packages/inter-protocol/test/vaultFactory/vaultFactory.test.js
index 66e179ca645d..f285b00bd00e 100644
--- a/packages/inter-protocol/test/vaultFactory/vaultFactory.test.js
+++ b/packages/inter-protocol/test/vaultFactory/vaultFactory.test.js
@@ -1838,6 +1838,13 @@ test('manager notifiers, with snapshot', async t => {
     }),
   );
   ({ vault } = await E(vaultSeat).getOfferResult());
+  totalCollateral += ENOUGH;
+  totalDebt += DEBT2;
+  await m.assertChange({
+    numActiveVaults: 4,
+    totalCollateral: { value: totalCollateral },
+    totalDebt: { value: totalDebt },
+  });
 
   trace('6. Loan interest');
   vaultSeat = await E(services.zoe).offer(
@@ -1851,18 +1858,21 @@ test('manager notifiers, with snapshot', async t => {
     }),
   );
   ({ vault } = await E(vaultSeat).getOfferResult());
-  totalCollateral += ENOUGH;
-  totalDebt += DEBT2;
+  totalCollateral += AMPLE;
+  totalDebt += DEBT1;
   await m.assertChange({
-    numActiveVaults: 4,
+    numActiveVaults: 5,
     totalCollateral: { value: totalCollateral },
     totalDebt: { value: totalDebt },
   });
-  m.addDebt(DEBT2);
+
   await manualTimer.tickN(5);
+  // This is interest for a single vault.
   const interestAccrued = (await E(vault).getCurrentDebt()).value - DEBT1;
   m.addDebt(interestAccrued);
-  t.is(interestAccrued, 9n);
+
+  t.is(interestAccrued, 9n); // interest on OPEN1 for 5 periods
+  totalDebt += 30n; // interest on 270_000 for 5 periods
 
   trace('7. make another loan to trigger a publish');
   vaultSeat = await E(services.zoe).offer(
@@ -1876,10 +1886,10 @@ test('manager notifiers, with snapshot', async t => {
     }),
   );
   ({ vault } = await E(vaultSeat).getOfferResult());
-  totalCollateral += AMPLE;
-  totalDebt += DEBT1;
+  totalCollateral += ENOUGH;
+  totalDebt += DEBT2;
   await m.assertChange({
-    numActiveVaults: 5,
+    numActiveVaults: 6,
     totalCollateral: { value: totalCollateral },
     totalDebt: { value: totalDebt },
   });
@@ -1898,11 +1908,10 @@ test('manager notifiers, with snapshot', async t => {
     }),
   );
   ({ vault } = await E(vaultSeat).getOfferResult());
-  totalCollateral += ENOUGH;
-  totalDebt += DEBT2 + 30n; // XXX ??
-  m.addDebt(DEBT2);
+  totalCollateral += AMPLE;
+  totalDebt += DEBT1;
   await m.assertChange({
-    numActiveVaults: 6,
+    numActiveVaults: 7,
     totalCollateral: { value: totalCollateral },
     totalDebt: { value: totalDebt },
   });
@@ -1925,20 +1934,11 @@ test('manager notifiers, with snapshot', async t => {
     }),
   );
   await E(vaultOpSeat).getOfferResult();
-  totalCollateral += AMPLE;
-  totalDebt += DEBT1;
-  await m.assertChange({
-    numActiveVaults: 7,
-    totalDebt: { value: totalDebt },
-    totalCollateral: { value: totalCollateral },
-  });
-
   totalCollateral += given.value;
-  totalDebt += WANT_EXTRA + 20n; // magic number is fees
-
+  totalDebt += WANT_EXTRA + 20n;
   await m.assertChange({
-    totalCollateral: { value: totalCollateral },
     totalDebt: { value: totalDebt },
+    totalCollateral: { value: totalCollateral },
   });
 
   trace('10. Close vault');