Anotherthing
Most of us fly 290 in the descent into London TMA anyway, what you say is understood on the line.
Lykra
Thanks for the lesson mate, I have been flying the bus since 95 so have a vague idea how it works (and no i have never modified the IDLE on the ground, but it is there should a company need it else why would there be an option). It doesn't take Mr Einstein to work out that you are burning more fuel with power on in the descent, if you were to select open descent at the FMGC computed descent point, you would go below the profile more ofter than not.
MF