A literal reading would seem to indicate that the allowance be reduced to 0-2.
That seems pretty sensible to me in the SRB case, but the same reading would also reduce things like "1 per Kn (S)" in French Ordonnance to "? per Kn (S)", which is historical nonsense (each Bw element contain the shooty parts of the lances (6-man administrative units) whose chargy parts comprise the Kn - you wouldn't have fewer shooters in each lance just because the entire army is smaller).
So it's probably best to say all "per" allowances are unaffected until an official clarification comes around.