But he has learned the tool. In fact he betrays his real frustration with Word: it's not with the Platonic model itself, but the fact that it betrays the model and uses some hidden logic (the >50% rule) to decide whether or not to actually apply the formatting indicated by the style. I've used Word for many years and have occasionally been stumped by seemingly non-applying styles. Now I know why.

This hidden rule should be the most heavily discussed 'feature' of Word. MS Office docs should trumpet it as loudly as they can. (Or they could just fix it.)