Well. So does it mean your mom needs to prepare enough for your 99 to distribute to her relatives and also to serve guests when people come visit the baby???
If yes. You should communicate with your mom early that she needs to make more.
Does it really matter? I think we should not be that clear cut as marriage is the linkage of two families. The point is whether you mom is happy to prepare for your 99 as well. Your 99 should pass on the Lai See to you / your baby instead.