This should be how both the iPhone and Android app work at this point (please let us know if this is broken for you on either of those). We still have not fixed this issue on the website, though it is something we plan to do.
This ticket came a long way looking at all the dates here. How come a simple feature as this is not implemented after this long time on the website? (after all, this is where you bulk insert expenses after a long trip)
Great idea, leaving it under review since we tend to be pretty conservative about adding new settings. Thanks for submitting!