Nationwide is my one national client that has not (this year anyway) asked me to reduce my fees.  I have never agreed to reduce my fees for any client, and I have never suffered any loss of work as a result.  They still call me every year and ask me to reduce them, I still say no every year, and they still send me work.  You just have to be politely stubborn. 

As far as paying, they have always paid on time.  And yes, they are looking for the lowest price first for their "non priority" customers, but if you establish a good reputatiion for turning orders on time, they will pay more money for their priority clients.  That is, I only do all of their rush orders because the turn time is more important for their priority customers than the lowest price.  This gives them an excuse to pay my fees, which are apparently higher than whoever they are using for their nonrush orders. 

Either way, I still get plenty of work, they pay my higher fees, and when I refuse to cut my fees they still send me work.