here would be my concern, you ask about a "per date" charge, there would be such a charge if you need a translator. The stand on the corner method will, if nothing else, get you a date, maybe just for the evening, but then you wouldn't be wasting an entire trip. It's best if you know at least a little Chinese, maybe enough to avoid a little 'neng pian, jiu pian' in Beijing.
It depends on what you hope to accomplish, if you're looking to sample from the buffet, the agency will attempt to help you, but I would not expect many willing dates, unless they are taking you to specific locations to ring the money out of you.
Anyway you slice it the way you're talking, you're talking getting taken to the cleaners. I recommend either going on qq and registering with their personals page, you'll make friends quick, unless you're rather ugly and hairy with no money of course. If you register a trip, you will get a people, from those areas offering to help you.
There are options, but bear in mind some of those options are not considered as desirable by the locals.
Lloyd