Anne
I've found that the off brands have the 2 envelope angel food cake I much prefer them if making a typical angel food cake. (but if I am making the one with pineapple and mandarin oranges then it doesn't matter in fact the one envelope is much easier...)
the brand I used yesterday is the company that took over Western Family and Associated I think and it's Food something in Albertson's it was the albertson brand I don't know if I looked at Safeway or not.... but gives you an idea of where to look. Also I always add again if it is the one in the angel food cake pan
an extra egg white as well as a small amount of almond extract... just my preference
sheila