I find that there seems to be more misinformation than good info being passed around at homebrew stores. I'm sure its getting better but I cant imagine what it was like years ago...
Biscuit malt is a bit different than if you toasted your own base malts. I think it probably has less fermentables left in it since it was toasted by a professional maltster. Also, 2 lbs of biscuit is a lot for a 5gal recipe, thats nearly 18%, more than the max given in the malt description. Personally (if you only have no other specialty grains on hand) I'd go with maybe 1 lb biscuit and 1 lb 2row. Or if you have time before brewing, toast some 2 row yourself in the oven.
hmm or......if you have no other malts at your house and dont want to make another trip, do 1 lb biscuit and add some cane sugar to make up for the other 1lb in terms of gravity. about 1/2 lb will do the trick. You'll have a slightly dryer body, but you could mash 1deg higher and probably wouldnt notice a difference...
It depends on the rest of the grain bill though. Is there anything aside from 2 row and 2 lbs of toasted malt?