Next question though:
As I understand it, managed descent is not available in HDG mode. Now around Europe it's very common as we know to be vectored parallel to your nav track.
The 737 (at least the recent -300s and all -700s) can maintain the VNAV vertical profile even if slightly off-track. It always displays the vertical deviation no matter how far off-track, based on where you are abeam the FMC track.
As it seems on the CBT, the A320 cannot do this, it drops to V/S as soon as HDG is engaged. It also seems to take away the VDEF indications on the PFD, so they can no longer be followed by the crew? It this true to real-life? Cause I can work out a semi-accurate descent profile myself, but fuel economy-wise having the optimum profile guidance (at least a VDEF indication) would help.