So this may have been answered, it may just be how things are.
Three different lengths of wood -
A)
I make a 100x50mm rectangle, save the face in my profile library.
I add the relevant tags, and use Quantifier to give it a cost of 1 euro per linear meter.
I use the Build tool to extrude a three meter length of said profile. Cost Detail Report confirms 3 euros.
B) (not using Build tool) I create a 100x50mm rectangle, extrude three meters using Push/Pull and Save as Group. I go to Entity Info and assign the same tag as above. Cost Detail Report confirms 3 euros.
C) (not using Build tool) I create a smaller 20x20 square, extrude three meters using Push/Pull and Save as Group. I go to Entity Info and assign the same tag as above. Cost Detail Report confirms 3 euros.
I then individually reduce the length of all three - A,B, and C from 3 meters to 2 meters using Push/Pull.
Cost detail report:
A - 3 Euros
B - 2 Euros
C - 2 Euros
In summary, it is not possible to resize items created by the Build tool, somehow it retains their created length and area as essential categories (although I notice that surface area etc IS updated, which is counterintuitive). However anything with the same Tag created without Build can be resized and its length and cost will be automatically updated, not limited to profiles with the same initial dimension as the desired Profile, but anything with the tag.
This leads me to think that not using Build tool, and instead assigning tags to created members/groups, is the smarter way to go for in model editing whilst tracking costs where ‘Push/Pull’ is used a lot for convenience.
Have I got this right?