Don't know why, but sometimes when you build something go in the CV, go in command view, drive around and stop to build something your calculator will not have recharged. One day it's going to cost me a game.
just to add... it also stops recharging for a moment whenever you change to another weapon and back to calc.. so the more you change weapons and back to calc.. the slower you will get a full charge.. a detail though
This is more easily fixed than the commander issue. After quickly checking, ammo regeneration when holstered works based on how long the weapon was away. So if you didn't have it away long enough it resets and you get nothing. The commander one probably works the same way revive does, your weapons are destroyed and recreated when you stop being commander. Ammo is controlled by the weapon itself so if it was destroyed, it's not regenerating. And currently I think there is no code that takes over this behavior to control how much ammo it would give you back when you stop being comm.