I'm thinking that should be more like 22.75 Hamers...
The .5 is the Hamer USA Daytona neck on my Mighty Hamer Daytona Mite. Late 70s Mighty Mite(Wayne Charvel) Explorer body mated with a Daytona neck. Love!
So, if i calculate correctly, it should be 22.25 considering the 3/4 standard.