Confused by tempo track relationship to time signature

Hi all, I’m a little confused how Cubase is computing the BPM of my music.

I have a sketch of a song (see attached) which intends to start out in 4/4 time with quarter note=55 bpm, and later shifts to 12/8 time with eighth note=165bpm. So I have a tempo track and a time signature track corresponding to that. However, instead of transitioning to eighth note=165bpm, I have found that it is running at double that speed (as if I had commanded quarter note=165 bpm). In order to get the tempo right, I need to set it to half speed (82.5, as shown in the screenshot) and then it comes out as I intended.

My question is, what exactly does this tempo value represent? I mean, obviously I’ve figured out that for my project it’s implying the beat rate of a quarter note, but is that always what it represents, or is that just because of how my project is set up? Is there a way to get it to follow the time signature? What if I had a particularly strange meter like 15/16, where timing in quarter notes doesn’t really make much sense at all?

It doesn’t really affect my current project as I’ve found what works, but I’m trying to get a better understanding of what is going on here so I don’t get stuck in the future. Thanks for any advice!

Cubase understands only quarters for tempo. Any value you see at the tempo track is quarters per minute, and not any beat per minute. Of course this is confusing, and many times I pull out the calculator.

There have been requests to allow the tempo track to understand other values, at least from version 8.

The most recent one is by me, here:

https://www.steinberg.net/forums/viewtopic.php?f=309&t=203559

Add your +1, and who knows.