if you buy above market price (which CMs do not), then you may lose some money in that Gaz, but you are right, they pay market price x Q = total paid by population. you have the risk of losing money on it even if it was set 120. example: construction @254 when bought by country and then the price drops to 180, you will still lose money, since you bought @ 254 and sold to citizens @ 180.
Tmac is correct. It does add welfare points, it does increase corp production with higher welfare. you should end up with a better end result and it should cover any losses you get from your above message. if corps produce 1/2 % more it should cover any loss by extra profits. if the Q game is working right, it may require less units of supplies to supply the country. not sure if GM has implemented it in this way or not, but that is the theory the game is moving towards. weapons and ammo is mostly effected by the quality already. a 360Q weapon will use 3x more am