The licensing policy is same and it is not changed. Earlier before Parallels Desktop 10 it was not necessary to create an account to register the license and it was allowed to use the license on a secondary Mac in case the original Mac was replaced or changed but now the usage of Parallels Desktop needs an account so if the original Mac is replaced or changed then Parallels Desktop license can be transferred to the new Mac. If you were using the license on two Macs then it was over usage of the license. If you wish to use Parallels Desktop on additional Mac then you have to purchase a separate license.
I'm afraid this is not correct.
When I look at my installed products in my account, all my older licenses could be used on 3 computers.
It's only with V13 that this was abruptly brought down to 1 (without any warning I have to say).
Most software publishers, including MS, Adobe and far smaller ones, allow for the software to be installed at least on two computers, and in Adobe's case even on two different platforms (one mac, one PC).
So I'm afraid you're about to lose another customer to VM Ware, unless you revert this policy and bring the number of allowed installed back to at least 2 computers (one desktop, one laptop). It's insane to ask the same user to pay for two licenses of the same product, especially when there is no simultaneous use, which can be easily checked.
By the way it's not practical to ask the user to deactivate/uninstall between two computers. First because it's just a hassle, second because it's often not possible. If you leave with your laptop, you can't go back home to deactivate the desktop before you can use the laptop. It simply doesn't make any sense.
I am shocked that you can seriously ask a a user to buy two licenses so that they can use the same product, not simultaneously, on two computers.
Please escalate!