Yeah, I was just reading another section of Mapping The Atari and it wasn't as complex and then the bit column thing all of a sudden made sense....and was a bit redundent. I don't need to be told that if I add 2, that both bit 0 and bit 1 will be set. So, now that I understand, the value set in Fort A would equate to..
Enable Missile DMA & Enable Player DMA
Enable Instruction to Fetch DMA
Funny how the brain works, and doesn't, some times. :-)