I'd see it where WoB sells the Mech Factory components to Comstar (at cost), but reserves the commercial rights to the Mech. So Comstar buys a factory, the equipment to make the factory, plus the Mechs themselves, and has to provide training/security. WoB instead builds a factory on a Protectorate world, and cranks out the toy version of the Mech, because every kid must have the latest toy to complete their collection. No security needed, locals are already trained for this sort of work, and a much larger market.
Presto, WoB makes back its money in the factory many times over, while Comstar is desperate for donations.
