NFHS double libero wording issue?

[SNIPERBBB]

Looking at the wording in the new books, I'm wondering if this will cause issues...

ART. 1 . . . Procedures for libero replacement:
a. The libero designated on the lineup for that set is allowed to replace any player in a back-row position. The libero may serve in one position in the serve order;

b. The libero may only be replaced by the player whom the libero replaced;

As per usual NFHS hasnt copied directly from another rule set that allows double liberos.

So if we have Libero #1 and Libero #2, and #1 has replaced back row player #3..can #2 replace #1 or does #3 have to come in because of the way B is written or does the wording in A allow the lib #2 to replace #1