My understanding is that Denon offers two lineups of receivers to different sales channels, eg. 1905 to the upscale stereo stores, 985 to the mass marketers, sort of like the different GM brands.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8