diff --git a/yarn-project/end-to-end/src/e2e_bot.test.ts b/yarn-project/end-to-end/src/e2e_bot.test.ts
index 00c5b06e16c3..78a1f6affff9 100644
--- a/yarn-project/end-to-end/src/e2e_bot.test.ts
+++ b/yarn-project/end-to-end/src/e2e_bot.test.ts
@@ -134,8 +134,9 @@ describe('e2e_bot', () => {
         // TODO: this should be taken from the `setup` call above
         l1Mnemonic: new SecretValue('test test test test test test test test test test test junk'),
         flushSetupTransactions: true,
-        // Increase fee headroom to handle fee volatility from rapid block building in tests
-        minFeePadding: 9,
+        // Increase fee headroom to handle fee volatility from rapid block building in tests.
+        // Fees can escalate >10x due to blocks built by earlier tests and bridge operations.
+        minFeePadding: 99,
       };
 
       {
@@ -174,8 +175,10 @@ describe('e2e_bot', () => {
         // TODO: this should be taken from the `setup` call above
         l1Mnemonic: new SecretValue('test test test test test test test test test test test junk'),
         flushSetupTransactions: true,
-        // Increase fee headroom to handle fee volatility from rapid block building in tests
-        minFeePadding: 9,
+        // Increase fee headroom to handle fee volatility from rapid block building in tests.
+        // This test is especially susceptible because changing salt triggers a new bridge claim,
+        // adding more block building on top of what earlier tests already produced.
+        minFeePadding: 99,
       };
 
       {
diff --git a/yarn-project/stdlib/src/gas/gas_fees.ts b/yarn-project/stdlib/src/gas/gas_fees.ts
index ca2e700c27da..7387b2df0496 100644
--- a/yarn-project/stdlib/src/gas/gas_fees.ts
+++ b/yarn-project/stdlib/src/gas/gas_fees.ts
@@ -56,8 +56,14 @@ export class GasFees {
       return this.clone();
     } else if (typeof scalar === 'bigint') {
       return new GasFees(this.feePerDaGas * scalar, this.feePerL2Gas * scalar);
+    } else if (Number.isInteger(scalar)) {
+      const s = BigInt(scalar);
+      return new GasFees(this.feePerDaGas * s, this.feePerL2Gas * s);
     } else {
-      return new GasFees(Number(this.feePerDaGas) * scalar, Number(this.feePerL2Gas) * scalar);
+      return new GasFees(
+        BigInt(Math.ceil(Number(this.feePerDaGas) * scalar)),
+        BigInt(Math.ceil(Number(this.feePerL2Gas) * scalar)),
+      );
     }
   }