Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hi,
I have the vertical hit and miss engine from Jin in China. I think its a nice piece of kit and I am contemplating buying the horizontal hit and miss engine as well.
However on Jins Ebay site there are now 3 different versions of the horizontal hit and miss. The M90 which we know and has been around a while. The M92 which has a side shaft and a vertical  rotating governor. Also there is an M94 with a different finned cylinder head and gone back to the older flywheel weights?.

So I am confused about the timeline of the M92 and M94. I thought the M92 was so new that hardly any have been delivered yet?
So where has the M94 come from?
There are also vast price differences for the same product on his Ebay site.