Okay, so doing a little searching I found this great article here on MacRumors
With watchOS 9 on the Apple Watch Ultra, Apple introduced a new battery feature called Optimized Charge Limit, which uses on-device machine learning...
www.macrumors.com
Apparently, the watch optimization is smart enough to learn your usage habits and create an acceptable level of charge for your watch based on what it thinks you will need.
So, in my case, 80% will not always be consistent based on my daily usage pattern.
For the moment, I'll let my watch do its thing automatically as I normally don't use 80% battery before charging on a regular basis.