I don't have OR forms, so I can't see what's available, but if you make the entry in Forms Mode, and it's on that Oregon ASC form? See if there is also an ASC "worksheet" in the list, and make the entry on the worksheet and not directly on the ASC form itself. But, perhaps there is no worksheet.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
