I do agree with you, to a point; my issue has always been overthinking, and further to that, thinking that I should increase the boil time to get my volume where I need it. And for a few brews, that meant having less in the fermenter than I intended. Now that I have done the boiloff test, and the math, it makes more sense to add the hops based on the volume rather than the boil time. I still keep an eye on the timer, but my main goal is to have the right volume at the end of boil. If the sight glass says done, but the timer says 15 more minutes, I'm going to agree with the sight glass. If my gravity winds up a few points off my target, I'll mark it down to experience and work more on my starting volume. Either way, I'm making beer; a few ABV percentage points doesn't bother me a bit. Currently sipping on a truly delicious light (4.6%) lager that was done with paying attention to the volume rather than a hard and set timer, which wound up at just the right volume & SG based on my math. Of course, to each his/her own, but this worked for me.