Problem with the alignment of the faces of Paneling Tool

Hello I am an apprentice of the plugin and I have a doubt to be able to make the plans for the carpenter to

make me these pieces that the plugin has developed,
the faces do not make them completely straight and there is a curvature on each face. Is there any way to make the faces completely flat, to be able to make them with flat wooden plates?

I’m doing something wrong, because I can not align the plane well, always get up one of the corners

thank you


Curved surfaces do unroll with curves, but surfaces with straight edges should unroll into straight edges.
Can you share the file?