Gottcha
We are currently play-testing house-rules that allow dedicated specialist ATGW units to fire on command through-out the game turn, so each move, as long as their Command roll is passed.
This doesn't apply to other units - so Infantry AT (LAW, Carl Gustav, RPGs etc) or RCLRs only fire once + vehicles like BMPs with Saggers or Sheridans with Shillelagh etc. only get the one shot per game turn as per the rules, and then only in Initiative.
One of the issues with the points is that they really cannot take into account the historical development of ATGW - so early in the period they are rarer & expensive and can be relatively deadly but the number of rounds carried was often low (partly due to cost).
Later they are more common, still expensive but relatively cheaper, with more reloads available (often even spare launching stations) and also highly effective, but so are the counter measures they are up against.
It's a tricky balance to achieve.
The points change idea you have put forward is an alternative and looks OK.