Confirmed! YES, you CAN use LATCH (LA and T) in HBB mode.
This comes from a reputable source who heard it directly from Graco in writing (thank you Kecia!) and we both agree that Graco should put this in their FAQs so it's in writing and people don't have to 'take our work for it'. (She is going to work on that through the mfg rep.)
Though I know in this case, CTB will take my word for it.
I know several other friends using their GNs this way, so I'm very relieved to hear they didn't change the rule!
Dogz, no apology necessary. We're all human, and often mfgs change things up on us but there's no central repository where we can get an easy answer. Sometimes it's hard on us techs! I've often come across threads like this and learned something new.