Proportions....

[PvK]

I suppose, to get the fleet training, although bases already get to-hit bonuses from mounts (or fire control centers, in Proportions), and currently you can retain the old base resupply technique, if you like it, by changing settings.txt to allow fleeting with bases. If bases worked the same way as fighters do now, and it wasn't optional, then it would be impossible to do that.

PvK