4—Whenever possible, the original surface of the sheet shall be
unaltered. However, where testing machine limitations make it impossible
to follow the above criterion on the unaltered sheet, one or both surfaces
shall be machined to provide the desired dimensions, and the location of
the specimens with reference to the total depth shall be noted. The value
obtained on specimens with machined surfaces may differ from those
obtained on specimens with original surfaces. Consequently, any specifications
for flexural properties on thicker sheets must state whether the
original surfaces are to be retained or not. When only one surface was
machined, it must be stated whether the machined surface was on the
tension or compression side of the beam