I can't figure out the strip surface function (came close but the report was about half made up of 0.000s) so I've decided to offset my OG the depth of my stripping and then balance my cuts & fills.
I made a copy of my OG, lowered it by 300 mm, this was reflected in the stats, but when I run my template through both surfaces I get exactly the same OG elevations.
Any idea why??