No No fella - not doubting you at all, rolling roads are notorious for guff results, and at the end of the day the only real way to prove it is on the track / strip. Years ago I was well chuffed to get 280 BHP from my C1J
Then got rinced by a 180bhp car. Point is, I will never know if the 180bhp car was 180 bhp, but I know now that mine was nowhere near 280bhp.
If you have got 240 - 250 nice one, that should really go well.
BTW - after that I took my car to 2 different local RR's and got 30bhp's difference between the 2. Same day. Same set up.