Actually, I'm happy to report that that is not totally correct!
Only half of "Standard Ship Movement" is used to calculate Combat movement. Extra Movement Generation is not included (and I believe neither is Movement Bonus). I've just tested a ship that ziped around the map at a speed of 21 but in the combat simulator, had a combat speed of 1.
If this is of interest to you (or anyone), contact me and we'll talk more about this.
rp@telus.net