Buying Premium when having multiple accounts in Google Play
I have two accounts in Google Play.
I bought Locus Pro in one of them and I use the same account for Locus Store (where I bought LoCoins).
Now I installed Locus 4 and I want to pay for going Premium. I click that I want to subscribe and google's screen with subscription overview is displayed, informing how much I'm going to pay now and how much I'll pay for next year. When I click the subscribe button at the bottom of the screen, it goes to next Google play's screen where it shows that Mastercard-*** will be used and it wants the password. BUT - the email address written at the top of password editbox is of my second GPlay account and I cannot change it. I suppose that if I provide password, different (the second one) GPlay account will be used for purchase. What shell I do to change the behavior?