It's certainly something we would like to offer and it's been looked at in the past, it does require a lot of work so it's not something that would be done overnight.

Any changes like this we would certainly keep you informed if it was to become available.

looked at in the past, it does require a lot of work

From experience that's a no then

"it does require a lot of work "

Perhaps the effort could be put to some use that will benefit more people than the few that want the ability to select their billing date.