help with rough opening suggestions and corrections w/picture

[surf_n_bid]

finished a install with a monessen direct vent and noticed some discrepancies in the owner/ install manual or maybe its me... the manual states rough opening of "41.75 inches height" and "do not use flanges for framing or header" , "for drywall support only" BUT my header is at the flange? any input or suggestions appreciated? i really don't want to start cutting up the framing...
(broken image removed)
screenshot software for windows

(broken image removed)

 

[DAKSY]

Definitely contradictory. If you're worried about the location of the header, replace it with a steel stud.
If you've met the specifications for the rouch opening, I wouldn't worry about it, tho.
I've installed hundreds of gas ZC boxes & screwed EVERYONE of them to the header...

 

[surf_n_bid]

thanks for the reply daksy... really needed yours and others professional advice on this situation.