I have a Kahles Helia 3-12x56 scope (some instructions refer to a ZF95). I am delighted with it but the original instructions that I have are in relatively poor English. I think that they are telling me to unscrew the centre locking screw by one complete turn, adjust elevation/windage, move the outer ring to zero to enable a quick visual check that there has been no movement in the future and finally screw the centre thread a complete turn in reverse. Can anybody tell me if this is correct - or perhaps explain in your own words?