This issue may have been discussed already but the current licensing model for Elevate where you have to put a license on the AP side is going to cause problems if we need to replace an AP for some reason and could mean having to buy licenses more than once for the same set of subscribers as the license is tied to the AP Mac address. Why not just have the license on the elevated SM? You could have the SM come up initially without a license and then loose its config after 24 hours (or some reasonable time) if a valid license isn't put on the unit. At least then if an AP fails you don't have to go and buy more licenses again for the same subscribers. Please take a look at this issue as it is not fair to have a licensing system whereby you could end up being charged multiple times for the same set of subscriber modules!
For one, there is an order of magnitude more CPE's than AP's in the usual environments.
Then there is the issue of hardware failure. You can transfer the license from one AP to another in the event of a hardware failure of the AP (Via cambium support, you send them the dead radio). Think of the nightmare of gerenciating such a scheme with the CPE's.
The final argument would be that the whole point of Elevate is to relieve the ISP of the headaches that the UBNT software causes, without the need to truck-roll and change things on the customer's houses.
Moving licensing to the CPE's would create one more risk factor to the remote equipment (that cannot be validated pre-migration). Imagine a 10% failure rate of license-validation on the CPE's. It would counter the whole point of elevating in the first place.
I think that the AP-licensing scheme is still the best and most flexible option for big systems and full-migration scenarios.. Altough there is a proposed "floating-pool-licensing" scheme that would be even more flexible. I would not touch a system that required validation for each and every migrated CPE. That has a high potential for headache generation.
If you can transfer licenses in the event of hardware failure then there isn't really an issue, other than possible delays getting a replacement sector loaded with the correct licenses, but I haven't heard this from Cambium themselves so maybe they could comment on that here?