Hi Sean,
Thanks for adding support for capturing reduced-amount orders. I tried a bunch of scenarios using/not using the new field at the bottom of the order screen and my impression is that it will be confusing for admins, since they have to make sure they do their change, then save the order (saving updates the amount in the capture field you added), then click the capture button you added. If the user instead does: change->save->complete->save OR change->complete->save, the original amount authorized is charged to the card (ie user must remember to click the capture button or the full amount will be charged).
I think it would be a better behavior to transparently process the order as was done in the previous versions: when the admin changes the order to completed state and saves, striper does submits the updated total to stripe.com. I think it will be the cause of fewer headaches for the admin.
The way I foresaw it working was: if the order is being reduced, the admin consciously removes items and recalculates taxes and the total, then marks it complete and does a save to capture the (reduced) funds and notify the customer that the order is complete. In the case where a customer is adding more to the order, the admin knows the order has to go back to pending and a new invoice with pay link has to be to sent and the old authorization to cancel. So there is little danger an admin will accidentally capture the original amount on increased orders.
Bottom line, and sorry for this long ramble, is there any advantage in exposing the capture button/field?
John