Are they overfeeding?

My 3mo son is breastfed on demand for the most part (Altho it typically falls around every 2 hours) and when I'm at work hes bottle fed breast milk. Our ped told us to feed him 1-1.5oz every hour so usually he has 3oz every 2hrs unless hes sleeping, then just whenever he wakes up. 3 nights a week hubby's home and has no problems with feeds. Once a week his parents babysit for us and they always make comments about leaving enough food for him even though I always do if they feed him accordingly. So tonight when I came home they made the same comments "hes so hungry blah blah" (he wasn't btw, he just missed me) so I asked when they had fed him and they said they were feeding him 3oz every 1.5hrs. I know they think he only cries when hes hungry but he actually cries for tons of reasons and whimpers when he's hungry. Are they overfeeding him or do you think he needs more? Thats all I produce when I pump while I'm gone (sometimes its more than I produce) so I'm not sure. Really could use some advice.