Confusion about the GNSS height encoding

[tdonovan4]

Hi,

I'm having trouble finding information about the GNSS height encoding.

The book states that when an airborne position message has a type code between 20 and 22, the 12 bits of the altitude field are used to encode the GNSS height in meters.

However, I can't seem to find anything in DO-260 about this encoding in meters.
The only thing I could find is that the encoding of both barometric altitude and GNSS height is defined in the same paragraph and this paragraph doesn't seem to distinguish between the two.
Am I missing something?

Also please note that I only have access to the original DO-260 and not the latest version, so it might be the issue.

I appreciate the help.