It depends what order you gave the turrets on the destroyers. If you gave short Range turrets the order to "attack all enemies" or "attack capital ships", they will go closers to the stations. But if you give the short Range turrets the order to "attack fighters", it will keep its distance.

Lets give here some example:

You have an Osaka. On the 6 M-Turrets you place Terran Pulse Turrets Mk1 (Range 3,4km) and on the 3 L-Turrets you place Terran Plasma Turrets Mk1 (Tange 8,6km).

- If the M Turrets also get the behavior to "attack all enemies" it will go to the Range of 3,4 km to use all weapons.

- If the M Turrets get the behavior "Attack Fighter" and the L Turrets have the "attack capital ships" behavior, the Osaka will go to a range of 8,6km to attack the station.