I switched to M1 SS 10w30 in mid December (engine feels great! ). For the first 500 miles or so w/ in town driving, dipstick level didn't move. I just got back from a 2k road trip to OK and I had to add about a quart and a half within that period. I've read here that when one switches to synthetic, the engine tends to burn more oil to begin with then tapers off. Was this burning due to this or because of the continuous high speed driving (70-80 mph) or both?