summary.nblastfafb subsets for the top N hits and only then calculates and reorders by mu_score. This leads to two potential problems:
(a) If there are nblast hits with high mu_score that are not among the top N forward scores, they will not show up in the summary.
(b) Probably less of a problem: if the original order (which is based on forward score) is changed by the user, the summary will be different. This could of course also be intended.