After discovering the oil useage I swithed to 10W40, not the High Mileage though. Didn't notice any difference. Even a new PVC valve had no effect.
Anyway, the multi-grade oil shouldn't give you a problem with the low temp, just don't try that with straight 40W. I did that once when I was a dumb first time car owner. Oh well, it started again in the Spring, lol.