If you have 4 trainees training on one position, and they are all on the same 8 hour shift, you can’t train each of them 2.5/3 hours. It’s also not a daily goal. It’s a weekly goal. The ATMs are wrong and NATCA has allowed the NTI to evolve into something it’s not. It was meant to be a focus on training and an effort to qualitatively evaluate training roadblocks, and it’s been turned into and FAA yes-man contest.
I’ve seen positions that in no way shape or form should be split be split, with no traffic, just so a supervisor can check the box that training got accomplished. When you rig the data by training at all costs in spite of th= goals and objectives of the NTI you lose all ability to analyze and use the data gained in anything approaching a meaningful way because that data is no longer reflective of reality.