Hawaiian's Baggage FAQ on the site regarding the new fee for a second checked bag indicates a domestic to international connection would be regarded as an "international itinerary", indeed, most airlines consider any itinerary that includes international flights to be an "international itinerary" and apply their rules accordingly. You can request a copy of the entire Contract of Carriage by writing Hawaiian or enquiring at a Hawaiian ticket counter. The document will provide explicit definitions for when international policies apply vs. domestic policies. The Contract of Carriage is the legal document governing your ticket purchase and bears more weight than a simple written statement from HQ.

Hawaiian could even be considered generous for allowing 70 lbs on flights into PPT. Of both carriers serving PPT nonstop from the US, Air Tahiti Nui and Air France, neither allows more than 50lbs per bag in the Free Baggage Allowance, and their charges for excess are higher.