I was trying to figure out if I needed to recommend a client file MFS instead of MFJ, and ProConnect, after splitting the return, did not calculate the phase out of the SALT deduction correctly. Instead of 30% of every $1 over the $250k, it was only reducing the SALT deduction limit by 15% per $1.

Anyone else see this or know how to fix it? If Proconnect's calculation was correct, I would have recommended MFS for my client, but the $1,200 liability difference caused by the calculation error took away the value proposition.