Even the title of this thread is wrong and ambiguous. It is wrong because HP5+ is not an ISO 800 film and nothing can made it so. (ISO has a meaning!) And it is ambiguous because it can mean three completely different things: HP5+ under-exposed by one stop, or HP5+ pushed by one stop, or HP5+ under-exposed by one stop and then pushed by one stop.
Yep - should be HP5+ rated at an EI of 800. And there should also be a reference to the development used.
But at least with respect to the development, that was made more clear as the thread evolved.
And as for your options, I would add a 4th: HP5+ metered at 800, because of the metering technique I prefer.
It's mind blowing how we managed to build so much obscuring complexity on top of a fairly simple exercise of dosing light and chemical exposure to silver salts to convert just the right amount into metal.

