If the union and company said it's OK, I guess go with that... Here's the applicable contract language;

Section 11.3.g.ii

g. Flying While in Long Term Training

ii. A Pilot who enters Upgrade/Downgrade Training and who is scheduled for time off between Ground Training and flight training may elect to pick up Trips or reserve periods during such time off, provided that the Pilot is upgrading/downgrading in the aircraft he was flying immediately prior to entering training. In addition, any Pilot who is scheduled for time off prior to commencing the "Systems" portion of Ground Training may elect to pick up Trips during such time off. Any flying that the Pilot adds will be credited over and above the monthly guarantee and will be paid at the premium rate.

I would probably have interpreted that as Mesabah did and say once you start sims you're no longer scheduled for time off between ground and flight training, you're now on a break between flight training and flight training but it's not my opinion that matters....