@katemoir - this still does not hang together.
Can you elaborate on a few User Scenarios, without asking just us to read the Guarantee?

Scenario 1
A user buys XWD365P at v12.0.0 and renews annually for three years.
After letting the Guarantee lapse, what version can the user download for a clean install?

Scenario 2
A user buys XWD365P at v12.4.0 and renews annually for two years.
After letting the Guarantee lapse, what version can the user download for a clean install?

Scenario 3
A user buys XWD365P at v12.0.0 and lets the Guarantee lapse.
There have been 27 bug fixes and 6 updates to v12.6.0. What version can the user download 3 months later for a clean install?

Scenario 4
A user buys XWD365P at v12.4.0 and lets the Guarantee lapse.
There have been 23 bug fixes and 5 updates to v13.2.0. What version can the user download 15 months later for a clean install?

Feel free to change the scenarios if you can illustrate any aspect more effectively.

Acorn