Build tolerances are much much tighter than before. Because of this there is less 'wear in' on all components. Of course there is going to be excessive levels of metals during an oil analysis because it still is a break in, but no where near the quantity or time frame as 20 years ago.
I would run the oil to half of the recommended service interval. The do normal service intervals after that.
Read closely in your owner's manual. I'm thinking that your 3.6L is the same/similar to what I have in my Enclave, and requires a DEXOS compliant oil.
