General SAM question

[anticlimacus 0]

Hello, just installed SAM for the first time and so far it's working great!  I'm able to make my guy more muscular using the Samson setting, however, the settings specific to Samson (waist size, etc.) don't seem to have any effect  I'm trying to modify my shape with narrower waist (basically, a leaner body style) but can't seem to get the body-specific settings to do anything.  I suspect I'm just missing something.  I'm using a Samson setting of 15, no Samuel.  Any help's appreciated, thanks!