HELICOMPARITOR,
Thanks for the explanation and yes we do have the options in the CAT A supplement but your are right CHCs philosiphy is to keep it simple and we tend to use one of either two profiles VTOSS = Vy or VTOSS = 55. These two profiles enable us to "shortcut" the performance tables provided we have encompassing critieria of ADSR and ambient T & P parameters, which of course are tailored in ABZ to temperate Northern climatic conditions.
We do always have the option of resolving the solution longhand and I guess if we were to maximise the opportunities without a backtrack we could do this.
You make a good point and there is probably an argument for revisiting the issue formally to create more flexibility. Maybe I will pass this on to our Technical Pilots and see what can be done.
Thanks.