attacking ?

I noticed that if I have a ship in orbit and then leave and attack on the same turn that the ship maintains its attack bonus from being in orbit. I ran it through the combat simulator on the GC web sight and a dozen times in game to see if the results matched up. Only when I used the attack values for the ship while orbiting in the simulator do the numbers match up with in game results. I'm not sure if this is as intended, and thus my question, is it intended? Am I missing something?

~SDC~