I can create multiple IT-203-F schedule B forms using the Mac Premier version, however the software seems to still think that you need to fill out Schedule A, which is mainly for termination agreement or non-compete income.
The values in line 20 of Schedule B seem to be used nowhere in the tax return when done, it seems the software only cares about Schedule A. The NY income should include the sum of all line 20 values across all completed Schedule B forms.
I think the way around this is to not fill out IT-203-F forms, instead fake a allocation number via percentage method, then at the end, manually edit the NY (and other state, if any) forms to use the real value as determined by filling out IT-203-F by hand, and instead print out and mail the NY return with your hand-edited IT-203-F forms.
Intuit needs to fix this to support filling out Schedule B only and using the sum of all Schedule B values as the final return value.
