Moderator: Hawaii-based airlines & Hawai'i forums
Join Date: Mar 2003
Location: Ka ʻĀpala Nui, Nuioka
Programs: NEXUS/Global Entry, Delta, United, Hyatt, IHG, Marriott, and Hertz
Posts: 18,692
There are specific rules on types of vouchers and if they can be combined or not. I don't recall what type the VBD ones are, but I have been able to combine them with the vouchers you can get when the price of a booked itinerary goes down after purchase and those are issued as Type B vouchers.