oh yea, depending on just how deep into the physics of it that you wanna go, there is wavelength dispursion calculations, efficiency's to consider, spectrum considerations, all that... but i would mostely agree with the above, that with t5's the w/g rule starts to get a little blury...
and your right, i would much rather someone tell me"hey, i dont know, but whaddya say i find out and then we can both learn something today" than lie to me... cause i will come back in the store, and i will find you and i will explain it to both you and the manager if i find out you lied to me, and it cost me $....
but thats just me.... some people are so anti confrontational, they just put up with it...its sad...