Form 8936 s-corp commercial vehicle

[Countingcat]

As an S-corp, I'm filling out form 8936 and 8936 schedule A for a commercial EV. When I get to the final answer on Schedule A it says to transfer that number to form 8936 line 19. Then I'm supposed to put the credit on line 20 for an S-corp. Line 21 adds line 19 and 20 together.  This makes no sense as it doubles the credit. Which line should I use to enter the result of Schedule A and which one should be 0?

[PatriciaV]

Since you are claiming the credit on an S-Corp return, you would enter the amount from Schedule A only on Line 19. If you received a Schedule K-1 from a partnership or S-Corp, you would enter the amount from the K-1 on Line 20.

See the source for Line 20 here: IRS Instructions for Form 8936 Part V.