Hello,
It looks like you have to mark the stock as "Undefined" at Machining and Part level so that the plugin will ignore it, see attached image.
Yes, but how ? .... I tried to write "Undefined" and this is not working ; the only way I found is to set all the six values to 0.
That sound like an "erase stock" plugin to do

I mean go quickly back to the original default where no stock exists. Not even stock with zero dimensions.
When no stock exists, on a new file, all values are set to 0 except the colors
Also selecting another material in the list do not change the stock dimension, unfortunately stock dimension are not stored in the material list ..
++
David