Walther pinwheel calculator Mod. RMKZ 22502 vintage antique

Description

Walther pinwheel calculator Mod. RMKZ 22502 vintage antique
CARL WALTHER
Abt. Rechenmaschinen ZELLA-MEHLISi.Thuer:
Modell RMKZ No. 22502
Based on the S/N it was made between 1931 & 1945.
The instruction on the bottom of the machine translates to:
Loosen this screw as far as it will go before starting
Tightening the screw locks the carriage in place when the machine is transported.
It has been well maintained and lubricated with a light oil recommended by machinists.
Note that one of the feet is not original, but looks like it was replaced at a contemporary time when the machine was first used.  The nut and bolt also look different and the nut is steel.  I did not remove any of the feet.
The calculator has aluminium-alloy castings, a setting check dial, tens-carry on the counter, but no back-transfer mechanism. The carriage is spring-loaded and is moved one step at a time by two vertical levers next to the winding handle. A button at the front releases the carriage to allow continuous movement. The accumulator register has small fiber thumb wheels next to each numeral wheel to allow values to be entered directly to set up division.
The last wheel of the counter showing 7, 8 and 9 in the 8 position on the left shown in photos doesn't zero when all of the others are by rotating the crank.  However, the 10s carry over from the 7 to the 8 position works.  I can rotate the dial wheel by hand to the zero position when the crank is moved off the locked position.   See photo.  Nothing is jammed or broken.  I wonder if this is a  feature of this model.
I strive for same day shipping and 30 day returns according to eBay rules.