I agree and am seeing the same thing WRT line 30 miscalculating when a carryover is present. I did some additional "testing" by plugging in different numbers:
If you have 2020 carryover but no 2021 benefits (ie line 10 on W-2 = $0.00) (my situation as well) then you have to do the "penny hack" to trigger the form, AND ALSO it does not subtract the carryover on line 30 of the 2441 as you have described. Looks like two separate bugs related to carrroyver and 2441.
If you have no 2020 carryover but 2021 benefits, it handles that correctly, subtracting the 2021 benefits from expenses as expected.
If you have both 2020 carryover AND 2021 benefits, it combines the two behaviors above : even though line 28 adds both 2020 carryover and 2021 benefits correctly, in the end at line 30 the 2021 benefits get subtracted out, but the 2020 carryover gets ignored.
So, in addition to the "penny hack" bug, Form 2441 line 30 is NOT handling the 2020 carryover correctly, even as line 28 is calculated correctly.
