The freeze dried has all the water removed, so technically you are getting more food so wouldn't it be a better deal? With the frozen, you are paying for the moisture?
Not sure, just throwing that out.
I think you'd have to do a side by side comparison and not look at the volume in the bags. I know when I use the S&C I use the freeze dried. I usually feed 1/3 of a patty at a meal (mixed with a pinch of ZP or a tablespoon of canned). A bag lasts me foreverrrrrrrrrrrrrr.