You are exactly right. Trump will have to needlessly waste time defending the pre-packaged headline “Billionaire Trump only paid $750 in taxes”.
It doesn’t matter what Trump says ... the headline has already been written.
I would think that POTUS defrayed expenses, and if this is for FY 2017 he had no income as it goes into a blind trust controlled by others. His money is making money he doesn’t pay taxes on unless he takes the profit.