Anyway, I imagine one could also (perhaps tediously) "reset" the SMA quota after the problems are due. This would probably be the most reasonable way for me to handle it if people have trouble. Can one do this globally for a subset of the problem sets, or would I have to do it "manually" for each problem?
No, I meant doing a new version for credit. That is weird - I just tried now and indeed I could do a new one. I do sometimes cap SMA but but this had been based on student reports. Checking it myself (yes, I should have done that the first time) you are correct. Thank you.