I would think - as said - that a PRESELECTION for 1% seems wasteful.. Who would take all those values to be kept in store in the meantime?? So may be order triggered (!) selection will take place...
Every manufacture has natural variation in their processes. To try and design different processes to make the various tolerances offered is near impossible and would be even a greater cost for the customers, it's just a selection process to grade for desired specifications.
Lefty