Hello there! (Sorry I thought I already answered this but it didn't show up!)

Great questions! I hope I can help clear things up:
-The first time through a sheet, I would circle any problems the students had wrong and let them try again if I noticed it was mostly calculation type errors. If it was clear they were totally confused or lost, I would make a note to try to work with them one on one or pair them with a buddy who had already passed that level (ie a group 2 student to help a group 1 student).
-On the actual test out, I let them have 2 errors total and still pass because no one is perfect! :)
-One thing I noticed is that if a student had a lot of errors, I could often give them a clean copy of the sheet they were working on, actually demonstrate with the first problem on the sheet how to work the problem and then let them try the rest of the sheet, they were able to find success with it. Most of the time the students were only to do 2 of the sheets and then the test out page. If I noticed they'd had a lot of trouble on one particular sheet in that level, I might ask them to try a third sheet just to be certain since they have to pass the Test Out or redo the whole level. 99% of the time they were grateful for the third try just to make sure!

I hope that helps. Let me know if there is anything else I can make more clear! :)