Battery discharge chart variation

[Spade]

I have been looking up battery level charts online.
My own batteries are 12.8 volts after charge and measuring with a multimeter after a few hours.
The different charts are showing 12.8 as high as 100% or as low as 70%.
I'm confused........

 

[autorouter]

Different lead-acid variations have slightly different voltages. For example flooded (ie liquid acid), gel and AGM have slightly different charts, as well as slightly different charging requirements. What type of battery is yours? Ideally use a chart produced by the manufacturer, but I don't think many do.