I'm not entirely sure if I'm correct about this, but before the new user shops, under the user dashboard the tally for how much sP you had counted how much was in your shop till as well, right?
I've noticed that since the new shops it only shows the amount of sP in your vault and on hand.
You're right, it did (and still does) count sP in old shop tills. I have 2.5mil still in my old shop, and it's being counted on my dashboard. Nothing from my new shop though.

I didn't see this thread and just posted something similar in the 'Gallery / shop feedback (not limit)' thread.
Anyway glad I am not the only one that has noticed and misses this working properly.
I could be wrong (it's been a long time since I dealt with Sarah's quests and the sp limit), but I think since the new shops aren't counted in with the overall sp tally, Sarah and Saggitarius aren't really working correctly? As of this post, my overall on the preferences page is 340,241 sP, but my new shop till has another 240,066, which means I should be able to do Saggi's quests and not Sarah's, but instead it's the other way around. The limit is tracking money locked in trade offers -- I had 2m in one this morning and Sarah gave me the error message -- so it ought to be tracking money in the new tills too, yeah?
I'm pretty sure (almost positive) that Sarah and Saggi's limits never included sP in shop tills.
it's been five or six years since i bothered with sarah's quests, so i honestly don't remember how they worked and i'm probably wrong, i've just always thought it was the overall total and not just what was immediately available to you (ie/ on hand + vault)?
I used to do Sarah's quests whenever my sP got that low (which was honestly very often) even when I was working on the shop till achievements.
then i definitely misremembered, and that's pretty good to know. o: thanks for correcting me!
I've notified the programmer who has been working on the new shops. I'll let you know if there are any updates. :)