For all 3 levels I have used the Qbank the same way - going through the curriculum one LOS at a time, while reading schweser notes, doing the LOS questions, then the reading questions and study session questions. Then doing the EOC q’s from Schweser and CFA.
For L1 - I used it all the way through prep.
For L2 - I used it up until I started review, then just did the odd quiz out of it - didn’t use it at all the last month prior to exam.
For L3 - so far, have gone through about 80% of curriculum and have answered about 50-60% of the qbank q’s, but I find the “short answer” type questions on it lousy. I stopped doing the study session quizzes because of these. I expect to stop using it in about 2 weeks, except for maybe the odd quiz as I go through my review.
For me, Q bank is still important in my study plan, but not as crucial as in L1.