We are maybe talking different things, but of course the height difference along an angle is exponential! Literally how geometry works. The angle stays the same, but the height increases as you go along it.
A bit moot though, as it is pretty evident there is a height difference, which is what is making the roof wonky. And it is more than the 25mm tolerance, which at this scale would be imperceptible.
Reading this exchange is engrossing despite the fact I don’t have the slightest clue what either of you are talking about.





