Eg: I wish to move a T-80 MBT over Rough Terrain 1. The T-80 has 18 MP, Rough Terrain 1 cost 1 MP per 100 meters. I choose to move the tank 8 MP.
(This is where I get confused)
According to the Terrain Effects Chart, this will cost me 1 MP per 100meters.
So how does this work?

How does this configure to inches afterwards as well?
Note- I only wish to have the answers from those whom have played or play with the GHQ rules. I don't want answers from those who don't play GHQ rules...

Thanks