I think the 3 tier approach suggested earlier in this thread would be the ideal solution. it’s easy to understand, it’s transparent.
Looking at the proposed UI, which allows you to track your progress towards £100, there doesn’t appear to be any allowances for individual saves that are over £100, which does happen.
It also seems misguided to introduce this now. Not only because of, well, the world, but also because there is no compelling offering for those who are in this looking for returns. The savings account feature isn’t live yet for non-investors, neither is ChipX an option, so people end up paying £13 a year for what is exactly the same product. I get the need to bring in revenue, but it has be compelling for customers, which ChipX might be, but the current vanilla product isn’t. But I also get that I may not be the target market.
It would be nice to see the auto-save feature make some adjustments to reflect the new fees. So if it would just have tipped you over the £100 for a 28 day period, it should be aware and favour saving a slightly lower amount. Otherwise you’re open to accusations of the AI arbitrarily pushing users over the threshold just to take additional revenue from them. I’m not accusing you of doing this, but I give it a month before someone notices they auto-saved £101 automatically, gets charged, and blames the AI.