Faustus' Black Market's ilvl range ?

I just assumed that he gave you items where ilvl = clvl.

Yet someone just posted in chat an item supposedly from Faustus 1 level higher than theirs.

Anyone knows what the range is ?
(And if there is one, then there's an interface bug, since the Alt-view shows clvl as ilvl, and not a range.)

(One level more or less can matter, especially compared with shipping...)