OK maybe I'm missing something here but...

I have a client whose W-2 has $3,500 in Box 1. Then in Box 3 and 5 it shows $3,200.

Box 7 (Tips) shows $300 in tips. So, I deducted the tips on Schedule 1-A. (She's eligible)

AGI in this case is $3,500 because there is no other income on this tax return.

On the Illinois return, it starts with AGI (which of course includes the $3,500 above).

I'm not understanding why you would EVER have to add back on the IL-1040 the tips that were deducted on the Federal tax return since that Schedule 1-A deduction takes place AFTER AGI. Am I missing something??