Why does my Android OS state that there's, "Not enough free space to install the program", when there's plenty of free space?

Why does my Android OS state that there's, "Not enough free space to
install the program", when there's plenty of free space?

My hard drive on my smartphone has 100 MB free, and the app I'm trying to
install is 2 MB.
I just recently deleted apps totalling to about 88.3 MB, and the computed
size has already been adjusted, and is displayed on the screen.
However, I have to wait 10 or 15 minutes to install it.
It's as if the updated, computed space is not registered in some way to
the operating system immediately.
It's Android 2.3.4 Gingerbread, no root, no unlocked; factory pre-set all
the way(not for long though).
So, basically, is that the problem? Why do I have to wait a while after
uninstalling apps, and re-computing space availability to above par to
install a new, extremely small app, to actually work?
Is this all the OS's fault, or is something else at play here(e.g., hard
drive or circuit-level operations reigning outside the control of just the
OS software)?
Because if the re-computed size is what it's going to be, at least let the
end-user know that rather than give the impression that you have the
available space, but it won't install anything.