Try browsing for tickets with and without private browsing enabled, and from different geographic IP addresses, from different computers, and different websites (cheapair, Expedia, Orbitz...). You should definitely see a fluctuation in prices, for the same seats. I always do.

It may well be that elite members get lower prices, as this may be the way for the airline to maximise their profit off you. Their algorithms are quite inscrutable, intentionally so.