Is it fair to expect a lower rate from a Provider whom you've seen in the past thru an agency, but whom you're now booking direct with? If so, how much less? If she was $1,000 thru the agency, what's a fair rate direct?

It can vary.  Sometimes, the reason they aren't booking through the agency is because they think they can get more money on their own.  Sometimes, they may think that if you're paying $1K to an agency you can pay the same to her direct.  On the other hand, sometimes, the rates are lower booking direct.  It can also vary depending on whether it's incall, outcall, at her home turf or on tour... there are a lot of variables.  One of the biggest variables is, of course, how much she enjoys being with you and another being how much she thinks you can afford.

I'd say a fair rate for a direct booking is anywhere from about $300 less than the agency rate to the same as the agency rate.

i have seen several well known porn stars whose rates are lower when you book them direct..you have to use the agency the first time you see them..then after seeing them you book them direct with private e=mails or phone numbers..if you paid 1200 for the first session..1k would be fair for subsequent visits minus the 200 for the agency booking..