t-bag,
Yes I agree totally with your point, and whenever possible we try to hand you off as early as possible.
We are told early in training to trasfer traffic as soon as it is clean, after all the earlier you chuck traffic at least it won't have a mayday on your frequency !!
The point is though, traffic has to be clean (ie not in confliction with anything else........even traffic in another sector).
Sometimes that requires holding on to traffic until it levels off........also don't forget we mat be conducting phone co-ordinations. You would not believe how long some phone calls with the military can be.
For example...........LJAO phone with a DTY Crosser......we need the FL, Direction of cross, SSR Code/Callsign and type of aircraft. Then we have to check that the cross can be approved given traffic, then we have to inform TMA North. We have to write strips ourselves.......this takes time, and is often enough for a radar controller to let an aircraft level off.
Just one example of the bigger picture, which is not always obvious from the flightdeck, but I would say that 100% of ATCO's I work with always try to transfer aircraft well before level off.
Regards