T32B threading queries

When I’m OD threading on my QT15n T32B the first cut seems to be huge and just tears into it!

Even if I put maximum no of cuts in, the first cut is too deep and so is the last 1 or 2?

I have changed the parameter for the final depth of cut but it doesn’t seem to make a difference

Anybody experience this? Of have any ideas?

Thanks
Marc