I just took my owners manual with me to buy motor oil for my first 2012 oil change (4K miles). The manual says 10W-30, SL or better, and not "energy conserving". Seems simple enough. However, I flipped to the back of nearly every jog of oil in the store, and only found one or two that was blank in the bottom of the logo. Eighty percent of the bottles had "Resource Conserving" and a few had "Energy Conserving". What's the difference between energy and resource conserving? Can I assume resource conserving oil is safe to use?