On the A340 I used to fly{now 747} our default descent speed was .82/320 to 10000ft then 250 same as everyone else.Descent in Managed speed,cos of the efficient wing always means descending well before any other aircraft I have ever flown.
If descent comes late due to ATC or whatever .Open descent with speedbrake does the trick to get back on profile.
I guess different company policy and ideas seem to indicate that .8/300 is often the preferred speed which means descending even earlier still. I suggest the ATC who asked about this if it is a problem with other traffic then keep the guy up longer but remember dont expect us to slow down and descend!!