Lear60fellow is right, post 26.
Use this; 1800 first hour
1400 second hour
1200 third hour
1100 fourth hour
2000 nm is pretty much the max under those conditions, Russian, unexpected delays, they don't let you climb at the start etc.
And; Last week I heard that one Jetflite aircraft got cleared by Moscow control to 15100meters (F495).
That was not a Learjet but a Gulfstream I reckon.
I know the manual says so but you have no business up there if you are even able to get up there which I don't think so.
The 60's aerodynamics start to change above Fl 400, you can feel it doesn't like it so much, in a fast cruise you can hear the winglets starting to rumble and the airplane becomes a little bit sluggish aerodynamic wise.
For what it's worth CK