Registration with multiple windows 7 accounts

This is what i find out:

I have installed a Windows 7 (ultimate) ‘family PC’ with three user accounts (my wife, my son and me).
I am the only administrator on this PC the other two are ‘Standard user’ accounts.
Only one of us use this PC at a certain time in a day.

I have installed Breakaway Audio Enhancer (1.30.02) under my account under administrator.
That is: right click and run as administrator.
After the install i have entered my licensed code and it worked perfectly.

Now comes my question:

In the other two accounts i need to enter the licence code too, after login.
I entered the same as above and it worked also.

Is this a normal procedure? Is a license for Breakaway on a user or per computer basis.

Thanks again for this great piece of software engineering.