You should be in range for the schools you listed, although a stronger GMAT will certainly help in your case because of your work experience (since these schools outside the top 16 like the Canadian schools are willing to cut a bit more slack to those with monster GMAT scores).
In your case, the potential concern an adcom would have is your work experience. As you may or may not know, the "teaching English in Asia" thing has a bit of a negative stigma because historically, it's been seen as a working vacation, a casual job, and not something that is equivalent to a corporate/office job. Traditionally, it's been the default job of choice for folks who didn't know what they wanted to do, traveled and landed in Asia teaching English. The industry may have professionalized, but perceptions take a long time to change, and just keep in mind that you may not be able to change someone's mind with just a few essays.
What you need to do is to do the best you can conveying the skills you learned in your job could translate into a corporate environment, and hope that the adcom who happens to be evaluating your file has an open enough mind to take you at your word (as opposed to defaulting to his/her negative perceptions of the job). It helps that you're not a teacher anymore but a manager, but just know that it's still an uphill climb.
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