Hi Vilas,
I think THR DES FMA has nothing to do with repressurization segment. Re-px is rarely required (if ever) and I'd expect SPEED-DES FMA...
I think Capt Mongo's explanation is correct - FMA goes to THR IDLE above the path, otherwise it's THR DES...
Bonus question - can anyone suggest a good, accurate formula for TOD calculation on the 330, taking into account speed, weight and winds?
On the 320 I was usually able to nail it better than the FMGC
On the 330 it's a bit more tricky, as this thing tends to glide much better...