I don't know if I can add anything you don't already know.. Here in Mass all we can get is your basic E-10. And I've had no trouble with it.

I do know that if the station doesn't "move" enough gas, the latter part of that last shipment in can separate and the E-10 can become E-40? 50? 60?

But by that same thinking, The alcohol supposedly goes to the bottom, so the E-10 could actually (potentially) become E-5 (7, 6, 4) all a supposition on my part! LOL.. I guess what I'm saying is you've maybe been running more ethanol than you know!