First let me state that I have 16+ licenses for Dopus 12 (2x5 pro, 6x1lite) plus the ones I have purchased for others... I've upgraded twice from 10 to 12, so I've been around the block a few times. I do not like the new licensing model, but I like even less how you've proposed the update to 13 as it seems like you're mixing your metaphors.
I guess I first need to state an assumption, which is once you get people on version 13 you never intend to do a major update charge again. So basically, although you've not explicitly called it out, you expect to start charging $25/license/year and along the way you'll eventually decide to renumber to 14 and then 15, etc, and these versions will all be included in the $25. It begs the question what will happen if people stop paying, and then want to come back into the fold later, but in order to keep that in line with what went before, one presumes they just start paying again and can rejoin the stream at the then current version.
I think the issue boils down to you're selling the past development, but people are buying the future support. You want to recoup your last 5+ years of making version 13, but I want to buy access to version 13 for another 4 or so years. This is probably an inherent discord between developers and users/purchasers.
Let me try to explain what I don't like. I'm going to use round numbers. If I pay $100 for a new license today, I would expect that to be worth about 4 years of updates... so that's $25 year. That feels roughly what you've be making in the past, based on the expense of updates and the years between them. So really, you should just sell licenses for $25/year starting now, and skip any upgrade fees... I suspect you don't like this though because it doesn't feel like you'll recoup your past development costs, but the users don't care about that... they care about what it costs today for future access.
If you never onboarded another new customer ever, then eventually you'd end up at $25/license as long as people considered the ongoing updates to the product valuable. I suppose the risk is someone would pay $25 for a license for one year, stop paying recurring fees, and you would be out the other $75 if they paid $100 up front. So the fix for that is either to require them to stay on board for 4 years to "earn" a permanent license, or to charge the $100 up front, but for 4 years of updates. The idea of pay $100 up front and then start paying $25 after one year, feels greedy and to someone who has tried in the past to promote the product, it makes an already difficult to justify purchase even more difficult to justify.
I think what I will probably do is just skip updating for long stretches, and then save up my $25/year until it amounted to purchasing a new license, and then do that. It won't cost me any more, but I will miss updates, but on the other hand I will technically end up with more and more licenses over time.
Let's look at the next ten years. My alternative is to pay 2x$146+6x$50=$592 now for one, or possibly two years (for a limited time), and then 2x$75+6x$25=$300 a year there-after. So in 10 years, I'd have paid almost $3000. Or I could spend $250 for five new licenses every 2.5 years and in that same 10 years have 20 licenses (more than the 16 I have now) for 1/3 the cost. I'm pretty sure I know what feels more affordable.
I suggest you either cancel this idea of yearly fees OR switch exclusively to yearly fees and cancel the idea of an acquisition fee. Either make every $100 of upgrade money get you 4 years of upgrades or make the upgrade $100 for 4 years or $50 for 2 years or whatever... but don't double charge. Your licenses might be worth $25/year or $100 for 4 years, but they're not worth the extra near term upgrade cost such that it will amount to $50/year over the next four or so years.