PAE15 Activation - 4 computers

Hello folks,

I use PSE15 on 4 computers thus I bought the program twice since there is a 2 computer limit.  I am unable to add the new serial number to computer #3 thus I have to keep deactivating one computer.  Do I need to create a new Adobe account so I can activate the third computer?  Please advise a course of action?

Thanks!