If it works, fine...
MA = Drive is Master
SL = Drive is Slave
CS = Assume Master or Slave according to cable position **
** Non-CS 40 wire, either position assumes Master
** CS 40 wire, Middle = Master, End = Slave
** 80 wire, END = Master, Middle = Slave ... all 80 wire cables are CS wired.
CS is just a way of automatically selecting Master or Slave - automatic, but not intelligent, as it will NOT work around a drive which is manually set to the wrong setting for the cable position it occupies - the only time it's likely to bite you, is if you reposition the drives on the cables and forget that they are not all CS.
One example, after converting my old setup to fully CS, and testing an old drive, I didn't have to worry if it was master or slave - CS and then it didn't matter which drive I borrowed the cable from.