Thanks for the clarification. The wording on the OR-A instructions is a bit different from the OR-1040:
If you’re claiming this federal deduction and itemizing deductions for Oregon only, don’t include the federal deduction in the charitable contributions you are claiming on Schedule OR -A
I interpreted the form instructions to mean don't add the $300 in addition to the itemized items from the Fed return, but concur with your provided answer.
