Graphisoft addressed this here:
http://archicad-talk.graphisoft.com/viewtopic.php?p=272323&highlight=schedule+decimal#272323. It appears to be a bug.
I'm trying to update all of my template schedules, and it seems AC21 has messed up some of the variables. Luckily, I still have our old schedules from AC20, which seem to still work, but I can't add anything new and have it format to the correct Dimension style.
Chuck Kottka
Orcutt Winslow
Phoenix, Arizona, USA
ArchiCAD 25 (since 4.5)
Macbook Pro 15" Touchbar OSX 10.15 Core i7 2.9GHz/16GB RAM/Radeon Pro560 4GB