I can understand why Bayarea want filters of the same brand/manufacturer.
I have a Hasselblad brand B50 Yellow-Green filter and and one Series VIII (ø 63) mande by B+W and there is a visible difference.
But, viewing, side by side, the printed pictures made with these filters (same conditions and film), there is no difference to be seen, among other things because these are shot with so different leses (angle of view) that it is actually incomparable...