Having a flick through the Somec catalogues, the only model using MAX was the Pro Max. There was a Pro Max CZ, but it has an Air fork and the funky Somec seat stay detail at the seat tube.
I reckon yours is the Pro Max in the 1992 catalogue:
https://web.archive.org/web/20200921...somec_1992.pdf
(See page 5, pity the scan is so lo-res)
I use those 1st gen Ergo shifters and they have never let me down...after I put some new g-springs in.