you can use several licenses for Cubase,Wavelab or Nuendo for example on just one USB eLicenser. you can also purchase another eLicenser for that but it is not necessary. you can install Cubase and even diffrent versions of it on so many computers, as you want(just for yourself, of course), on one or several, and you can use each program particular in the effect that you transfer the eLicenser to that computer, you gonna work to. you can not use one or several programs at the same time on different computers with just one USB eLicenser. for example if you want to work with two or more programs at the same time on two different computers, maybe for a pro studio setting, you´ll need another USB eLicenser.
hope, i could help you