I've tried slotting some maintenance engineers into my active space slots on a couple different characters. They are supposed to give a better cooldown rate or something to Aux to SIF and engineering team. Yet, slotting them doesn't seem to do anything at all, those two BOFF powers have the same cooldowns every time.
There was a bug for Maintenance Engineers and Astrometrics (both use the same power attribute under the hood) for which a fix is in the pipeline. I am not sure when exactly it will go to Holodeck, however.