Legal "shall" vs. "will"

A ProZ forum post quotes this summary of Bryan A. Garner’s explanation of "shall" vs. "will" from his A Dictionary of Modern Legal Usage.

1) American Rule:
shall = has a duty to
must = is required to (used for all requirements that are not duties imposed on the subject of a clause)
must not = is required not to; is disallowed from; is not permitted to
may = has discretion to; is permitted to
may not = is not permitted to; is disallowed from
is entitled to = has a right to
will = (expresses a future contingency)
should = (denotes a directory provision)

2) ABC (Australian, British, Canadian) Rule:
shall (not used)
must = is required to
must not = is required not to; is disallowed from; is not permitted to
may = has discretion to; is permitted to
may not = is not permitted to; is disallowed from
is entitled to = has a right to
will = a) expresses a future contingency
will = b) (in an adhesion contract, expresses one’s own client’s obligations)
will = c) where the relationship is a delicate one, expresses both parties’ obligations
should = (denotes a directory provision)