Just to play Devil's advocate for a second, I don't really think there's anything inherently sketchy about posting a salary range. Of course he's going to put the high salary in the title line, its an ad, its meant to grab your attention.
If this is a recruiter, he might be representing several schools, that all pay different salaries. Again, we come back to the fact that he's a recruiter. The range in and of itself isn't a bad sign. The bad sign is that he's a recruiter, not the salary he's posted.
Also, within a school, there may be a range of salaries. With my current school I made it clear up front when I interviewed that I expected to be paid at the higher end of the salary scale. However, I know for a fact that a fellow FT at my school makes considerably less than I do. We are also a Chinese international school (but one of the better ones, I think, from the descriptions I've read here and elsewhere), a private school. These schools will generally pay more and have a lot more negotiating room when it comes to salary. The teacher who makes much less than I do was teaching PE last semester, so his salary is quite understandable (I actually think he quite lucked out to be making what he did and teaching kids to run around a track and do jumping jacks in unison!). So even in a school, not all FTs are created equal, and there might be some range. Again, not inherently sketchy.
I don't know Allen Choi or his setup at all, and I don't usually like recruiters, but I am not one to talk because I accidentally ended up using a recruiter to find my own current job (I responded to a cleverly disguised ad in the Beijinger, but the job was good and the recruiter basically introduced us and then let me be). Even if he is a recruiter, I'd maybe drop a line about the job. Its likely to be a Chinese private/international school, but the pay is good, and if everything else checks out, it might not be a bad deal. You might luck out like I did, and you're not signing anything or promising anything just by responding to an ad.