Biakal IZH-46M Piston setting?

[Cynabal]

Ok I recently got a IZH-46M and after removing the grips and shaping them to my hand and then finishing off with linseed oil, I decided to strip the gun down to give it fresh lube, and familiarize myself with the gun and how it works.

When I removed the piston from the cylinder I noticed the piston itself is screwed into the linkage. The end of the linkage is threaded with 4 notches cut in at 2, 4, 8 and 10 o'clock and the piston has a hole at the back where a small screw goes in and holds the piston in place.

Picture

I took note of how far the piston was screwed in and which notch the screw was aligned with so I could put it back how it was, but is was thinking if you can screw the piston in and out of the linkage doesn’t this affect the compression of air?

If the piston was screwed right into the linkage then the distance from the head of the piston and the back of the compression cylinder would be greater and I'm guessing therefore the air wouldn’t be compressed as much when its cocked, and I'm thinking is the opposite also true, if the piston it not screwed as far into the linkage then the distance between the back of the compression cylinder would be less and the air would be under more compression?

I would have tried this theory out but I don’t own a chrono, and I don’t want to damage my new IZH-46M but I'm wondering if anyone here knows about this? As its obvious that the piston is designed to be adjusted hence the 4 notches.