Those numbers dictate the weighting the Pool uses when determining which pools to show you as Alive. If you have Nist5=1.2, it a multipler for avg mBTC/day. So say Nist5 is earning .002 per day and Qubit is earning .002 per day. If you have NIst5 as 1.2 then its effective Btc per day is .0024 Where as Qubit would be 1* .002 or .002. I use this flag and favor Nist5 more because it draws less power. Therefore even if Nist5 and Qubit are both supposed to make .002 really Nist5 would make more once you subtract electric costs. For instance Skein is .5 because the X10 only has 5GH/s of hashing power but online it shows Skein as earning .0035 per day which would be true if our machines could hit 10GH\s.

Does that help?