I don't recall exactly, but I believe it is substantially longer. And I'm not sure I agree about the original post, as I have made XA shots at night with a campfire in the scene on chrome film, and everything worked well. It is likely (this was many, many years ago!) that I used the backlight compensation switch which was sufficient to compensate for the brightness of the campfire.
I have also used either the backlight compensation or the fiddling with the ASA (so I could use the the self-timer) to help extend the exposure time on my XA. But I do think the idea in the original post would work as well.