I bought Hookpad Plus (the one-time $149 one) on July 20, and have been able to use multiple voices and all that. Today, I learned that it wasn’t working when I tried editing a tab with multiple voices.
In the TheoryTab drafts tabs, I get the “You don’t have Hookpad Plus” popup. However, loading the tab in Hookpad 2 or Hookpad 1.8 does not show this error.
An interesting thing to note is how the order ID is blank, and the card number is missing a digit (last 4 digits start with 0):