Thanks for the question, Mike. Think I understand what you're trying to ask, correct me if I'm wrong:)
The 12-month time period for free updates is the main factor here - whatever comes out within that time you get at no extra charge. So, if a 'beta' feature turns into release within this period, you get it for free. If a feature is in beta and turns into release only after your 12-month period expires though, you can get it as part of a new 12-month package at the cost of 45 euros. Essentially, after your 12-month update period expires you have another 12 months to opt to buy a new update package at that same price, so you can choose the best moment to do that (based on your preferred feature set, the program's performance, releases etc.)
Hope that makes sense.
3DC Support's post in If I upgrade to 2022, will V4 be unusable ? was marked as the answer