Hello,
I have thought some more on the topic of implementing a possibility for sellers to opt for "non-instant orders" - where buyers need to first open the order for discussion before payment [1]. This would allow the seller to double check on inventory availability, card condition accuracy and pricing issues, thus avoiding the fees and annoyance of refunds.
I have tried to sketch a couple of options, ranging from a simple info flag that would highlight sellers that ask for such a discussion before payment, to an option that does not allow the buyer to pay before the seller "confirms", much like the trades have a "propose" - "accept" flow on both sides.
I have decided in the end that all the solutions have a bit too many downsides, and in the name of simplicity we will remain with the current system. In all cases there would be too many loopholes where sellers could lowball the pricing, only to then later bump it up after an order is discussed, or be negligent with inventory since cancellations would not incur negative feedback, etc...
The interface is also getting complicated, since the "special seller flag" needs to be displayed (and also explained) on card pages, on marketplace pages, on seller profile pages, on seller tradelists, on order pages, and on multi-order pages, where you'd have some of your orders be "instant", others "wait to discuss them" before you can click on "pay for all".
I'm not saying the feature request was not reasonable, and I do empathize with the issues of keeping accurate pricing and inventories for occasional sellers that have a job and life outside of magic, and not much time, but I could not find a solution that felt clean
All I can promise ist that I will try harder on keeping deckbox pricing more correct, and less "laggy" in catching up with price spikes, as much as i can.
[1] https://deckbox.org/forum/viewtopic.php?id=31339