Does it really matter? It's only for bragging rights at the pub, anyway!
If tuning is planned, repeated runs in identical conditions are required in order to illustrate the difference to each state of tune. Whether the end result is measured in widgets or whatnots is kind of immaterial, surely?
As Vspec ro rightly ended with, if you're happy now then be happy!
If you wish to go faster, that car will become a money pit very quickly. I'd be very interested in a tune that saves 10mpg..!!
