Victor 500-series with 9 columns - what model no.?

[Thomas Kirchhof]

Hello,

today i got an old Victor adding machine, s.n. 218871 (built maybe ca.1934?)

It's very likely from the 500-series, but what is the exact model no.?

Usually the 500s have 8 or 10 columns, but this one has NINE! 

I have never seen anything like that and can't find any info about 9-column-models from Victor...

...anybody here who knows more?

Thanks and

kind regards,

T.