Whew, though I don't use pre-packaged mixes, at least I know I'm not "losing it".
I actually like your mix better. It looks like a good combination though I would want that perlite in it just to keep it open and well-draining. Scheflera plants are tough cookies and I have only found one sure way of killing one, other than pulling it up and tossing it. They don't take freezes well. I had several dozen last fall, had no way to over-winter them, and left them out, knowing they would not survive the winter. They didn't.