If you're going to do an oil analysis, and you've just switched brands of oil, wouldn't it be better to do the analysis after you've changed the oil twice? The first batch is still going to have some of the old brand in it, albeit a small amount. (And if you've been using an inferior oil before, the results could be skewed because of deposits that the new oil would be cleaning out on the first go-round.) The main reason I'm asking is that someone posted in my thread about my switching to Rotella T Synthetic asking if I was going to do an analysis. I probably am, but I'm going to wait until I've changed the oil again and then do it on that batch.