Normally the VNAV descent mode will start with 1000 fpm, if below the optimal idle thrust profile. Some people prefer this way, 1000 fpm until intercepting the vertical guidance for idle descent, then dive with 2800 fpm. This will make the controllers nervous now and then, since they see you coming close and the original vector with 1000 fpm points way behind the restricted waypoint.
Sounds like a mis behaviour of the SIM sw, or improperly set up mode. On the real aircraft, the FMS guidance will work, that's why it is there in the first place.
Another approach to the task, using the x5 rule is this:
DES to FL 110 from 210 = 100 levels to go.
Distance is 30 nm, so times 3 you could conveniently lose 90 levels. (it's conservative)
Being slightly above the math already, there is no need to delay the descent.
Check GS, i.e. 456 kt, and "halv it" = 23 ..=> 2300 fpm is what you need to achieve 3°.
Set V/S 2300 fpm, put the seat-.belts on and fasten the shoulder harness. Re-attach the headset to your skull, start the sterile cockpit mode of thought. Smile and enjoy doing a good job, focus on what's ahead.
The advantage of true VNAV is the machine can cover for variances in wind in different layers, speed restrictions and ISA deviation. Provided you load the box correctly with accurate data, although satisfying both of these requirements is a bit of a drag now and then. The above "times 3" and "half GS" method never failed anyone. It is great because it provides you with 2 pieces of much-required information
- how far from the desired profile you are
- which V/S you need to make good in order to stay on it, or fly parallel.
I.e. when 2000 feet too high and GS showing 384 kt, if already descending on idle thrust and the resulting V/S is 1400 fpm:
a) the aircraft is deviating further above the profile
b) the aircraft is flying parallel to the profile
c) the aircraft is flying steeper than the profile angle, and wild eventually intercept it from above.
You know the answer.
(cross-posted)
EDIT: out of interest, what IAS would you normally fly in such an exercise?