:) Usually it goes in steps of 16, 32, 64, 128, etc. 48 is a bit unusual, and depending on hardware I guess could cause some issues (it's usually best to have matching paired sets, so 2 x 8 for 16, 2 x 32 for 64, 4 x 32 for 128, and so on - 48 would suggest there's not an even match of memory sticks in there, and can affect things like how the CPU can address and access the memory, but it could be fine depending on processor, and exactly what you have, could be 2 x 8 + 2 x 16 for instance - but it's "odd" as in "unusual" :) ).
Anyway, memory is not that sensitive - unless you run out of it, in which case it is the be-all-and-end-all :) You would get a Low Memory Warning from Corona when that happens though, something to always pay attention to if it pops up.