the problem is that the tortilla is very high fiber. although some fiber is broken down (by bacteria, i believe in the large instestine) and used, most is not.
fiber is not digested as are starches, which are primarily digested in the early small intestine, where glucose and fructose are transported into epithelial cells to be transferred to capillaries to enter the blood and be taken to the liver, muscle, ect.
i'm not sure the phsyiology behind how fiber is used once it is broken down by bacteria, but it's in a different manner.
so to answer your question, as far as energy differences, YES there is. even if the portion of sweet potatoe contains 19g (6oz potatoe contains more than this) of carbs, like the tortilla, the difference is due to the high fiber content of the tortilla.
now will this difference effect your bulking over the long term? i don't know to be honest.
are you getting in a good amount of starches in your other meals early in the day, prior to your workout? if you are, then i don't think it'd be a big deal.