One would think the result should be a perfectly formulated composite stream.
On the face of it, at least, the result should be a perfectly formulated composite stream.
THE PERFORMANCE PRINCIPLE: The performance of each ingredient feeder affects the proportion variability of all other ingredients in the composite stream, but only to the extent permitted by the Proportion Principle.
Thus, even though the desired 50/50 blend may be realized on average for any particular cross-sectional slice of the composite stream, the exact proportions of A and B remain somewhat uncertain.
B's persistent variability in the total formulation is due entirely to the fact that A's continuing +1% variability influences B's proportion in the composite stream due to the Proportion Principle.