glutes and estimated BF%

Is there any particular reason why these online BF% testers don’t take into account larger, more muscular glutes. I thought I’d give it a go and test my BF% this way to see how far along I’m coming and the stupid test is telling me I’m 2-3 % higher than I know I am (based on previous testing methods). I did some messing around with the numbers and found that the hip measurement was what was squewing it. Yes I have a larger hip measurement and to say the least a big ass. It is nearly all muscle though. In fact it is what enables me to do really low squats fairly easily without any hip/glute fatigue at all. These online testers seem to have a pre-programed set for what the makers think is the “typical” body composistion. I’m beginning to think they are not even close to accurate for most trained individuals. Anyone else have similar experiances/gripes? Maybe if I was a fat couch potato it would be accurate otherwise it’s a piece of junk. Don’t use them!