How does TAC support for pay-by-the-hour CSR1000V at AWS work?

Anybody using (or selling?) TAC support for CSR at AWS?

Apparently Cisco TAC support services for the pay as you go CSR is available for purchase through any Cisco Partner.

From reading further on that page, it looks like there are SKUs for various throughput levels and AWS instance sizes.

So... How does this work? Buy the contract and then attach an AWS UDI key?

Is there a way to handle ephemeral-ish CSR workloads? Like an auto-scale group for DMVPN or AnyConnect?

What if I do upgrades by replacing one CSR instance with another running a new software release?

The support situation here is kind of interesting... This is the only case I can think of where you license IOS(XE) with bug fixes independently of TAC support. (Yeah, I think that other thread shouldn't have been locked... Lots of interesting space to explore there.)