Hi, I'm not sure if you deleted your thread or something, but I answered this for you!
That's perfectly normal! The pores in the bag are clean and fresh now, allowing tons of air trough it. After a few uses, the pores will begin to clog with dust, and the bag will inflate to it's full size again!
P.S-you're lucky that bag didn't explode off the emptor from all that soot!