Not really. That quote alone could simply mean that as already black-majority schools become more black, that is, "increases of time," they get less total funding. But that doesn't mean that total per pupil expenditures of majority black schools are lower than white ones. In fact that would directly contradict that "on average, both Black and Latinx total per pupil expenditures exceed White total per pupil expenditures by $229.53 and $126.15, respectively" which is stated explicitly rather than "shift in ways that disfavor the typical Black student’s district relative to the typical White student’s district" which is ambiguous. I didn't read the whole paper but this quote alone doesn't mean anything. The fact is that black schools get more money according to that study.