I have experienced the following during vectors to land at numerous airports. Here is an example from CYYZAirspeed is 240; RC instructs to turn heading XXXdescend to 6000 feet, then 5000, then, while I am level at 5000 and 240 knots: "descend to 3000 feet", and a few seconds after that"reduce speed not to exceed 210 knots"followed less than 10 seconds (still trying to slow down before continuing descent) after by an altitude warning: watch your altitude, your assigned altitude is 3000 feet. I doubt that in real life ATC would not give the pilot time enough to actually slow down the plane. I have observed this at different airports. The software should be adjusted to give enough time for a slowdown. Cheers,

we'll see if we can't improve that in the next versionuntil then, i suggest starting the descent right away, all i'm looking for is negative vertical speedjd

Unless you are really close to a waypoint, start your climb/descent/heading/speed change before acknowledging ATC. As jd stated, RC looks for a change as a response so if on A/P as an example you can spin your control (and do a level change if using that type to activate it), ack ATC, and then finish fine tuning your adjustment to the actual value.