No! You can do this...
With the Business subscription you may assign the license to a maximum of five domains on any server within twelve months.
With the Professional subscription you can assign the license to a maximum of five domains with no time limit on any server.
With the Developer subscription you can assign an unlimited number of domains within the twelve months membership on any server.
The license is domain dependent, which is why you need to record the domains in your user control panel and use the verification tool.
At least that's my interpretation.
More here
Which License,
Terms and Conditions and
FAQ's.
If you're still unsure you should probably contact support or the accounts department directly.