The labelled set has a RIFF and the scan is unbounded, so it reads past the RIFF
there -- the headline number could have been borrowing discrimination that a
RIFF-less bank cannot offer. Confining the scan to the leading region gives
69.98%, which looks like exactly that problem.
It is not. Split by how much leading audio there is: on the 989 banks with >=24
packets of it, the scan is 100% correct with ZERO ties, whether or not the RIFF
is in range. The 69.98% is an artifact of short leading regions, where two or
three packets are not enough to separate candidates.
A RIFF-less bank is a whole pak entry, so 24 packets are always available. The
99.62% is conservative for the population the scan serves, not optimistic.
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