Training Status Formula?

Is the formula used for Training Status posted anywhere?

I found the following, but there are no details about the formula actually used.

I want to turn Training Status off on this device as I am sick of it reporting that my training status is just Maintaining despite doing training that I know is productive.

Personally, I wish the device could just report TSS, ATL, CTL and TSB after the rides. While not perfect, these make more sense when applied to my data.

Despite switching all the settings to turn off, the training status is still appearing after rides.

Currently running 5.31 Beta Firmware, and will update to 5.50 Firmware once it shows in Garmin Express.