No, it just annoys me that this gets repeated so often yet I can't find the source. Most studies I find only use signals 250 Hz and up. These studies aren't trying to find some lower frequency limit - I haven't found one that is trying to do that, it just seems that 250 Hz became convention, somehow.
Conceptually it's a super easy experiment to run, but the trick is getting LF drivers with low enough distortion close enough together to measure minimum audible angle.