My concern is that the certification requirements cover the enroute terrain consideration, which can be critical for some aircraft and, if one can't meet that, then the plan ought to be looking at a drift down while avoiding hostile terrain by the usual clearance requirement. Heading off with weights which would/might result in gross ceiling, coincident with hostile terrain, probably isn't a really good strategy.
I may have the wrong end of the stick from my reading of the thread .. in which case, I'll go quietly. Concern is to make sure that folks aren't forgetting the terrain and a need to have a bit of fat for the not-so-good days ?