I don't generally take measurements; it's usually just the mirror and the scale. But I would say that my body fat percentage stays pretty stable, and is low enough that I can notice if it fluctuates. I ran another, less intense cycle a few weeks ago and went from 162 to 168 over 5 weeks (though that includes a couple weeks where I stalled because my sleep was garbage). I lost little abdominal definition, but not enough that I feel any need to 'cut' body fat.
My own, amateur opinion is that most people should be able to gain lean mass without much fat gain, so long as they eat right. I definitely have to slam down the calories gain any weight, but I think one can shunt those calories to the right places by keeping their insulin levels in check (though certainly not zero). It also seems like many polyunsaturated fatty acids promote fat buildup in the tissue, so the bodybuilder staple of peanut butter might not be ideal for someone trying to gain weight while staying lean.
@Oscar is spot on. Different words that only mean slightly different things. 'Tis the lingo of A+A snobs; feel free to use the word 'sets' instead of 'repeats'. But don't say 'repeats' if you really mean 'sets' ?