The reason why the two accounts have different offers is because a lot of software nowadays has big data to kill the situation. If you are a new user, the software will send a lot of coupons or specials as a way to attract users to order to use, slowly generate dependence. And old users have used many times so the software will not bother to retain customers. Like many brick-and-mortar stores out there, there will be exclusive offers for new users, the principle is the same.
You can use the new account first, the old account if there is a period of time not to use if the software will also send some coupons to activate the old users