TOPIC: "Same as Registrant" option not always available

We would like all of our registrations to have the "Same as Registrant" checkbox available on the billing page, but it seems to be appearing randomly on some and not on others.

Any ideas on why this might be happening?
Thanks!

That box should show whenever you are registering for ONE event. When you use the multiple event registration option with the cart, that box will not show... as "same as registrant" would be tricky. If you are registering for 3 events (for example), the registrants may be different so it wouldn't know which one to pull from.

We actually do not use a cart or allow multiple event registrations. We do sometimes allow group registration (names/phone numbers only) with a single billing form at the end, but it's always just a single event at a time.

I haven't found any sort of pattern for why it appears some times and not others.
Any advice on things to check? Thanks