Why not make it a timed upgrade for a rifle squad?
...
I do think that usf is not at all well designed to be skipping tech...
The refit idea can also be implemented to other infantry besides refilemen like USF crew that have lost their vehicles.
The idea behind the USF faction was that they will have the best mainline infantry and very good light vehicles but less access to support weapons. The whole idea went to scrap when USF got a mortar, Penals become equally strong, VG got a ST44 upgrade and USF light vehicles where nerfed.
The where designed to skip tech and they worked when they early game was strong, now not so much.