I think a re-crewed support weapon's crew should have the default crew performance instead of inheriting the new squad's stats. A couple of days ago a Shocktrooper squad stolen a Rkw47 AT gun. Retreated and reinforced up to 6 men. The new soviet AT gun crew killed a G43 Panzerfusilier squad. The best part is you cannot easily tell what performance a weapon crew will have. No one zooms on the models in the middle of a fight to double check what they are. I have not expected an AT gun crew to destroy a 290MP + 90MU squad with no problem.