We have NAV 2016.
We've been paying (the 16%) for the "Enhancement Plan" for a few years, during which our partner has applied only 1 CU update (MAY 2017).
We want to stop paying $16k a year for this "enhancement plan".
1) Our partner is telling us that in order to update to the latest CU update, we must have this "Enhancement plan" that "gives us access" to the update. But the CU updates are available and free to download from Microsoft site, and there are also separate pages that Microsoft allows access to for free, describing the installation procedure for each update. If we drop this Enhancement Plan, does it really mean that we can't apply these CU updates?
2) If we drop the "Enhancement Plan" can another NAV Developer (that has a NAV dev licence) hop in and do a customization for us, or fix something in a current customization, **if the need will arise** in the future.
We won't be upgrading to NAV 2018 ...or to the new Cloud NAV
I don't know what they give you with the "nhancement plan": if they have some other vertical objects those may stop working.
For CUs you are right: You can download and apply the patch. However, it's not recommended to apply these patches unless you have some NAV issues. Patches have pieces of code that need to be merged manually by a developer, apply binary files in services, local computers....
hope this helps,