...that is in there now, you don't really need to hesitate leaving the Auto-Rx in for more than 500 miles: if the oil was pretty "fresh" vs. being at the end of the normal change cycle you will just get additional cleaning, up to the capasity of the filter, which should be pretty safe if you put a new one on.
Either on this treatment or the next leaving it in for 1000 miles shouldn't hurt a thing as it does not affect the lubricity of the oil. Some have left it in for their normal, entire oil change cycle and oil analysis showed no adverse effect.
I'm very interested in what the oil coming out of the pan looks like and what you find in the filter pleats as it compares to my experience. Maybe you better do it @ 500?
I also find it very interesting that some people are so of the belief that putting in anything other than oil is a waste of time and money because "it's ALL snakeoil"... If you took an MB into the average dealer (not under warranty) with a mechanical noise and they charged you $50 and the noise was actually gone(
!) most owners would be praising the dealer and thanking their lucky stars!
Hope it is a permanent fix! Cheers!