We build stairs differently in New Zealand compared to the UK and one of the main problems we run into is the wrong tread sizing. i will attach photos for reference.
our treads stop at the start of a riser ( refer to red line drawing in photo 1 ) and stair designer only gives us tread dimensions of the black line ( please refer to photo 1 ).

so each time we cut out or treads we have to manually calculate the real tread size as most of our stairs are carpet grade and we allow 25mm for nosing and have made mistakes in doing so which cost us alot of money and time.

i am looking for a solution for this, maybe there is a way to customise the method of stairmaking so we can remove the manual calculation out of the equation and follow a cutlist exactly.

i also have taken a look at each individual step to check the dimensions given and those also do not align with how we make the stairs.