Because the DMX-40-C and DMX-40-CE only has 40 channels, at most we can see they only support 80 channels, how can the systems support up to 82 or 41 channels?
15454 can support total 112 wavelngth 80 in C band and 32 in L Band.
But cisco have defined 82 wavelngths in C band and 80 Wavelngths in L Band.
So you will have ONLY 80 Channels in C band but if you have tunable laser it CAN be tuned over the 82 wavelngth defined by Cisco.
So 15454 support 80 channels from that 82 list
For DWDM wavelngth see the link