THIS IS JUST A GUESS
Considering the previously mentioned imperfection of the system, I have an assumption that the Standard license can be updated endlessly. That is, you need to have a friend who has Standard, give him money to buy an upgrade to Pro, and he will receive a new activation key - that’s 180 dollars. If you were just buying a license, you would have to give 300 USD. Theoretically if it is work - you could save 120 USD by this method. So total price of Pro for you would be not 300 usd, but just 180. Wow.
I am not hinting at anything and I am not advocating to bypass the system. These are just my guesses. Perhaps I should write a bug report about this rather than discuss it here. LOL, dammmn