Ohio State Taxes

Yes.   OH starts with the Federal Adjusted Gross income (AGI) and then allows OH only deductions to arrive at OH AGI as if a resident.  The resident OH tax is figured based on that OH AGI.  

Then based on the allocations of non-OH source income made in the OH interview, non-OH source income divided by the OH AGI gives a proportion which is then multiplied by the OH tax as if resident.  

That yields the OH non-resident credit that is subtracted from the OH resident tax.  The remainder is the OH non-resident tax.  

From there credits such as withholding are subtracted to arrive at a net tax/refund.