I suspect that Maxima makes many unnecessary calls to the simplifier,
both in the interpreter and in translated code. Many of these are
probably because there is not a uniform, clear convention on when
simplification should happen, and it is better to err on the safe side
(though unsimplified expressions still crop up in bug reports). Some
of these calls may be unnecessary in normal operation, but necessary
if the SIMP flag is being manipulated (which is rare, but occasionally
necessary).
-s