ATC has had issues with TOD and getting too correct RW, since release. The rule stated in the second post is correct and is excellent rule of thumb. If I am using the Navigraph FP, and import into 737 FMS, and then put in Star/sids correctly, it will show my TOD on the route if I zoom in enough. to see it clearly. I normally just start descent at 100 miles away from my final destination, if ATC is off, if on, I usually start at 90 miles regardless of what they say as it bogus in sim. Once I am within 10 miles of TOD, I change altimeter setting to the 1st point of the STAR altitude and keep changing it until I am on approach altitude, so plane get down to it. If short route to test something (RNAV Approach) I keep it set to the altitude on the chart for that route. If I fly higher, it gives me error in FMS when putting in altitude and waypoints. I am most likely doing it wrong, not RL pilot, but you cannot count on ATC in any of the sim I am aware of. Vatsim might be correct, but do not use them.