Her writing is clear, to the point and gets the message across with a minimum of grammatical errors. I don’t know what the target grade is for her students but

Her writing is clear, to the point and gets the message across with a minimum of grammatical errors. I don’t know what the target grade is for her students but it’s below a perfect native level score. If she’s intimately familiar with the grading rubric I can easily believe she can coach people on how to speak, read and write to a level that’s sufficient to get the grades necessary for her client’s purposes.