I agree with incognito isis, we all need to stay calm.
As a general rule I have not encountered this issue. That being said, it does exist. I have seen provider ads that between BP, eccie, e.com and P411 show different rates for what appears to be the same menu. Over the last number of years I have decided not to contact a few of those providers where that issue existed even though they interested me. I don't want to debate rates and understand not to ask so I am not sure how you would resolve the different rate issue other than staying away...but that is my problem. This is not a single provider issue and I do appreciate Irish Vixen's caring. It is also not a single client that has raised the issue. There have been threads on this board from more than one client mentioning the issue.
FWIW, P411 generally shows the higher rate when comparing multiple profiles with different rates. I have no idea why except that it may cost more to maintain a profile there and your costs are being recovered.
Oh well, that's just my 2 cents worth. Let's be nice to each other. We all have a common interest in getting along.