I've been noodling this since I first read the post yesterday.

I agree that you should stick to course until you start feeling and edge. Alternating doesn't really help at all.

Is M2 steel really harder than the Sharpmaker's ceramic sticks? - or at least that close to the hardness of the sticks? I wouldn't think so.

Like Stretch suggested, rather than investing in another sharpening system maybe its time to invest in some diamond sticks for your Sharpmaker. I've used mine mostly when getting a fast edge on really dull stainless steel knives, but it might help you with the M2.