I have modified my projects Style.cfg file to add 50 mm allowance to the cut length for all Field Fit/Shop Fit Welds in the Cut List and the BOM.
However, I am used to the standard convention on Isometrics of also displaying the additional length allowance as part of the relevant dimension.
EG: If I have a pipe with an elbow at one end and a flange at the other, with the weld between the pipe and flange marked as FFW. If the spool is 610 long from face of flange to centre of elbow, I would expect to see a dimension from weld to centreline that includes the allowance. Something like: 610 (+50)
In the image below I have manually edited the dimension to show how I need it to be formatted.
