No, you’ve understood it correctly. We always open in the default associated application. We don’t have a ‘transitive’ Open With option yet.
We try to keep it simple, and actually – try as I might, I don’t think I’ve had this request mentioned before… 20+ millions users and about 17+ years… It seems most settle on having one preferred application for a given extension.
I do understand why you’d want to be able to switch, but it’s not a common request apparently. Sorry, it’s not likely to be a priority in the near future.