With a low miles OCI, will it matter whether you're using a "mid-saps" or "full-saps" oil? Ie do the saps get used up by driving? I have one car which gets changed only every 2 years, but still very low miles driven (not short trips though). Thinking of going to 3 years, actually. So should I pay attention to saps at all? Currently using Valvoline 5W40 MST.