I've been working on a mission planning tool, and have therefore been gathering data about fuel consumption for Viggen at different speeds and configurations. In the data I could see some strange things happening.
One of those things were fuel consumption dropping with altitude, as expected. However when you get to 5km alt. it starts going back up again, to almost the same consumption as on sea level. Which it shouldn't be doing.
Another thing is the mach number at mil power. The mach number is the same until you get to 5000m, where it starts increasing smoothly, very close to the real values. Only 5000m offset.
At sea level with 92% NHT, you should have a mach number of around 0,67. In DCS it's 0,82.
The real data is from "SFI AJ37, del 3. Kap IV", page 11 and 16.
As with all data it's not going to be 100% accurate, so my measured values might not be 100% accurate, but quite close.
Feel free to have a look yourself.