2021 Form 1116 Line 18 not calculating correctly

Per the Federal Form 1116 Instructions - pages 21 and 22 - Individuals who completed the Qualified Dividends and Capital Gain Tax Worksheet (QDCGTW) , which I did, you MUST USE (REQUIRED TO USE) the Worksheet for Line 18 (page 21 of form instructions) to figure the amount to enter on line 18 if: 1. Line 5 of QDCGTW is > 0, and 2. Line 23 of QDCGTW is < line 24 of that worksheet. I meet the requirements to use worksheet for line 18. Using the worksheet manually I came up with a lower amount for line 18 which increases the percentage on line 19 and the maximum amount of credit on line 21 is larger. TurboTax is using 1040, line 15 on line 18 which it shouldn't be in my case.