I really feel you on this, prepping EBM in advance makes it so much harder to just wing it. Around 3 months, babies do get more settled and their hunger cues can become a lot subtler, so you are not imagining it. Your 2.5-hour schedule sounds totally reasonable, and if he is finishing his feeds well and seems content after, that is a good sign you are on track. If you are ever unsure, your PD or even the polyclinic nurses are really helpful for this kind of check-in lah, they can just confirm he is gaining well and the interval suits him.