The -ing form creates the meaning "the act of -ing" or "the process of
-ing". Other related noun forms do not necessarily create that
sort of meaning.
Analyzing those sentences was very instructive.
(The process of analyzing those sentences ...)
We need to do more sentence [analysis / *analyzing].
(Here "analyzing" would not be correct.)
The dryness of the clothes depends on the number of [spins / *spinnings] in the machine.
(Here "spinnings" would be incorrect. It's not the number of processes of spinning that is in question.)
CJ