Sub 20% transmission losses is less than I would personally expect and without Dave's engine having the map finished in the car, and being run on full boost I guess we will never have an exact figure to go off mate as to what he would have had, and obviously now he is breaking the car thats not going to happen now.

Even if it has lost 20-30bhp in the car for some reason, such as restricted inlet breathing or exhaust breathing relative to the dyno cell then I dont really think it matters a great deal to most people, although the numbers would have been interesting to see.

But for you to be arguing against what you think it might have done with the boost turned up, and then compare that to what you think it should have done, is all pretty pointless IMHO as its all entirely guesswork really, so if its 20bhp apart on a load of guesses thats still only a 3% error, which doesnt seem unlikely to me anyway.

So I dont really think you have any valid point that you are making TBH mate, it just comes across like you are having a go, even if that isnt your intention.

Dave put it on the dyno because he was interested to see what power he had been driving it with, he now knows that.
He also knows what the engine was capable of from the dyno, so trying to guess what its capable of by adding numbers to what it made on the rollers seems pointless when he already knows it makes 711bhp on high boost anyway.