diff --git a/src/forms/Y2020/irsForms/F8889.ts b/src/forms/Y2020/irsForms/F8889.ts
index 2e1d20005..abc1f0186 100644
--- a/src/forms/Y2020/irsForms/F8889.ts
+++ b/src/forms/Y2020/irsForms/F8889.ts
@@ -245,7 +245,7 @@ export default class F8889 extends Form {
   l14c = (): number => this.l14a() - (this.l14b() ?? 0)
   l15 = (): number =>
     this.hsas.reduce((total, hsa) => hsa.qualifiedDistributions + total, 0)
-  l16 = (): number => this.l14c() - this.l15()
+  l16 = (): number => Math.max(0, this.l14c() - this.l15())
   l17a = (): boolean => false
   // TODO: add in logic for when line 17a is true
   l17b = (): number | undefined => Math.round(this.l16() * 0.2)
diff --git a/src/forms/Y2020/tests/f1040.test.ts b/src/forms/Y2020/tests/f1040.test.ts
index d6d3ef05b..3d0bae284 100644
--- a/src/forms/Y2020/tests/f1040.test.ts
+++ b/src/forms/Y2020/tests/f1040.test.ts
@@ -1,4 +1,4 @@
-import { commonTests } from '.'
+import { commonTests, testKit } from '.'
 
 jest.setTimeout(40000)
 
@@ -13,16 +13,16 @@ beforeAll(() => {
 describe('f1040', () => {
   commonTests.run()
 
-  // it('should never produce higher tax than income', async () => {
-  //   await testKit.with1040Assert(async (forms) => {
-  //     const f1040 = commonTests.findF1040OrFail(forms)
-  //     expect(f1040).not.toBeUndefined()
-  //     // tax is less than taxable income
-  //     if (f1040?.l15() ?? 0 > 0) {
-  //       expect(f1040?.l24() ?? 0).toBeLessThan(f1040?.l15() ?? 0)
-  //     } else {
-  //       expect(f1040?.l24() ?? 0).toEqual(0)
-  //     }
-  //   })
-  // })
+  it('should never produce higher tax than income', async () => {
+    await testKit.with1040Assert(async (forms) => {
+      const f1040 = commonTests.findF1040OrFail(forms)
+      expect(f1040).not.toBeUndefined()
+      // tax is less than taxable income
+      if (f1040?.l15() ?? 0 > 0) {
+        expect(f1040?.l24() ?? 0).toBeLessThan(f1040?.l15() ?? 0)
+      } else {
+        expect(f1040?.l24() ?? 0).toEqual(0)
+      }
+    })
+  })
 })
diff --git a/src/forms/Y2021/irsForms/F8889.ts b/src/forms/Y2021/irsForms/F8889.ts
index 2e1d20005..e5b5b2f09 100644
--- a/src/forms/Y2021/irsForms/F8889.ts
+++ b/src/forms/Y2021/irsForms/F8889.ts
@@ -242,10 +242,10 @@ export default class F8889 extends Form {
   l14a = (): number =>
     this.hsas.reduce((total, hsa) => hsa.totalDistributions + total, 0)
   l14b = (): number | undefined => undefined
-  l14c = (): number => this.l14a() - (this.l14b() ?? 0)
+  l14c = (): number => Math.max(0, this.l14a() - (this.l14b() ?? 0))
   l15 = (): number =>
     this.hsas.reduce((total, hsa) => hsa.qualifiedDistributions + total, 0)
-  l16 = (): number => this.l14c() - this.l15()
+  l16 = (): number => Math.max(0, this.l14c() - this.l15())
   l17a = (): boolean => false
   // TODO: add in logic for when line 17a is true
   l17b = (): number | undefined => Math.round(this.l16() * 0.2)
diff --git a/src/forms/Y2021/tests/f1040.test.ts b/src/forms/Y2021/tests/f1040.test.ts
index 4537f9d0e..f747b8839 100644
--- a/src/forms/Y2021/tests/f1040.test.ts
+++ b/src/forms/Y2021/tests/f1040.test.ts
@@ -1,4 +1,4 @@
-import { commonTests } from '.'
+import { commonTests, testKit } from '.'
 
 jest.setTimeout(40000)
 
@@ -13,22 +13,18 @@ beforeAll(() => {
 describe('f1040', () => {
   commonTests.run()
 
-  // TODO: revisit this test. Commented it out because it will fail
-  // under certain seemingly legit circumstances. For example, if there
-  // is no income from W2 or 1099 but an excess distribution from a HSA
-  // is done, then there will be more tax than income.
-  // it('should never produce higher tax than income', async () => {
-  //   await testKit.with1040Assert(async (forms) => {
-  //     const f1040 = commonTests.findF1040(forms)
-  //     expect(f1040).not.toBeUndefined()
-  //     if (f1040 !== undefined) {
-  //       // tax is less than taxable income
-  //       if (f1040.l15() ?? 0 > 0) {
-  //         expect(f1040.l24() ?? 0).toBeLessThan(f1040.l15() ?? 0)
-  //       } else {
-  //         expect(f1040.l24() ?? 0).toEqual(0)
-  //       }
-  //     }
-  //   })
-  // })
+  it('should never produce higher tax than income', async () => {
+    await testKit.with1040Assert(async (forms) => {
+      const f1040 = commonTests.findF1040(forms)
+      expect(f1040).not.toBeUndefined()
+      if (f1040 !== undefined) {
+        // tax is less than taxable income
+        if (f1040.l15() ?? 0 > 0) {
+          expect(f1040.l24() ?? 0).toBeLessThan(f1040.l15() ?? 0)
+        } else {
+          expect(f1040.l24() ?? 0).toEqual(0)
+        }
+      }
+    })
+  })
 })
diff --git a/src/forms/tests/TestKit.ts b/src/forms/tests/TestKit.ts
index 48165c045..ac5a2096e 100644
--- a/src/forms/tests/TestKit.ts
+++ b/src/forms/tests/TestKit.ts
@@ -37,7 +37,11 @@ export default class TestKit {
     try {
       const builder = this.builder.build(info)
       const pdfs = await builder.f1040Pdfs()
-      const saveDirName = `Errors ${new Date().getUTCHours()}:${new Date().getMinutes()}:${new Date().getSeconds()}`
+      const today = new Date()
+      const dateStr = `${today.getFullYear()}-${
+        today.getMonth() + 1
+      }-${today.getDate()}`
+      const saveDirName = `Errors ${dateStr} ${today.toLocaleTimeString()}`
       const saveDir = path.resolve(logsDir, saveDirName)
       await fs.mkdir(saveDir, { recursive: true })
       await run(pdfs).fold(