Overriding AGI in Form 8962 to Figure Premium Tax Credit when self-employed (using Premier)

TurboTax is not providing the best numbers for a PTC under ACA. I am self-employed and able to deduct premiums. I followed IRS "iterative" instructions to come up with best numbers for credit and deduction. I now need to override AGI on Form 8962 to reflect the numbers. I followed TT instructions for override, but it doesn't work. Nothing happens when I click override or use shortcut keys. The credit difference is about $150 and the deduction difference is almost $900. So it's a substantial amount of money. Credit and deduction should add up to total premiums. Unfortunately TT is not providing numbers that add up. I don't want to do tax forms by hand but may have to. Any advice? Working in Windows. Thank you.