Approach question

[rickair7777]

Quick question. Hope I don't set off a chain reaction of people slapping their heads. I've had a few instances where the RVR was reported as say variable between 1600 and 2200. I would say this is fair game for shooting the approach if your mins are 1800. Any regs or publications that say otherwise?

Also, I had a night where the METAR for my destination (less than 1 hour away) was reporting 1/4 mile, but RVR was 1800. The guy next to me in the weather room suggested that I couldn't legally go because of the 1/4 mile, but I went anyway because there was an approach at or above mins. What was that about?
Thanks

In 121, if there is conditional weather info you have to go with the most conservative data, unless your operation has an exemption for that situation.

Not sure about 91 or 135.