I'd write to the scheduler, and tell them that you've done the shop before for a higher fee, and politely let them know that if they can't fill it and wind up increasing the fee again, you'd be happy to help them out.
I really think it's all in the attitude and the way you ask. I've had fees increased for two shops, after I had a dialogue with the scheduler. In both instances, the company knew that I was not making a threatening or frivolous request.