Is there any torque loss on a dynojet?

Hey, this might seem like a dumb question, but this is something I've been wondering for a while. I know Mustangs lose about 15% of their break horsepower through the trans., but do they also lose some torque? It doesn't seem like it really should, and I know what the definition of torque is, but I've seen a lot of guys pull torque #'s on a dynojet that are much lower than the advertised torque rating of the car. Do they lose some? Is is around a certain percentage of loss or do dynos just give estimations of torque based on the amount of horsepower? I tried to google this and look it up, but I haven't found anything. Someone please explain.
Thanks

How much of a loss though as a percentage? Is it the same amount as the horsepower loss which is around 15% on a T5?