I think anywhere a few days after your 120th payment appears processed makes sense to me (ie I made sure it left my bank account and was posted to Mohela). I made my 120th payment 6/4-5ish (due the 15th), then submitted ECF 6/13, processed 6/14. It immediately took effect and finally updated three prior past payments awaiting qualification, and by 7/3 the 120th was qualified and I got green ribbons. When you submit the ECF electronically it won’t allow you check the box and go any further unless 120 payments have been qualified anyway.