I suspect there’s more to it than just the MAC address. as I had a similar experience recently with one of my installations.
I had a failing laptop running Breakaway One from a near-new SSD. It used a USB Ethernet adaptor. I purchased a new laptop, but swapped the SSD from the old laptop and did all the usual driver updates etc. I also migrated the Ethernet adapter from the old machine, so, in effect, Breakaway One was still “seeing” the same MAC address and licence details. However, it went back to trial mode.
I forward the new config information to Support and they issued a new licence text file which worked immediately. Cmparing the text in the two, I could see some differences, so it may use the motherboard serial number or something like that as well in the algorithm.