If we talk RDSCALS, then the licence server will 'borrow' them for user/device that connect to any server that got the RDS service role.
For Windows CALS the calcul is not the same. You need a CAL per resource (user/device) domain wide. Each CAL cover the use of all your users on your domain. Just make sure you have the correct's one. (If you have 2008R2 user CAL, those users are not entitled to use 2012, 2012R2, 2016, etc.. ressource in example.)