Yes it is a commander.Don't change anything until you get about 500 rounds down range. 1911's are not like poly guns and have to break in. My Kimber bounced more than a couple of casing off my forehead while it was breaking in. Is this a commander sized gun by chance? Also, make sure you are running the gun lubed correctly. 1911 are like AR's and like lube.
there's a lot more to the 1911 extractor than just it's tension..
erratic ejection could be several things.
Loose ejector --- make sure your ejector is solid in the frame with the slide off...some makers are gluing in the ejector these days(sigh)
recoil spring binding --- I would suggest a 16 lb recoil spring for a std Government length model. no reason for anything heavier or longer. you also don't need any buffer, period.
extractor hook mis-shaped --- the bottom of the extractor hook needs to be tapered a bit ( see Wilson extractor tuning article on the web).. Also the length of the extractor more often than not is too long causing the hook to hit the case.. EGW HS extractor and their basic extractor are the shortest you can find.. the hook should not hit the shoulder of the case. it should only grab the rim... also the amount of deflection ( deflection is the amount of distance the hook is moved when the rim slides into position.) can cause issues with rims of varying size..
personally I'd replace the extractor if the ejector is not loose.. factory tuning amounts to checking tension at best. more issues are resolved by proper installation of the extractor in a 1911 than most any other part
That might be it.. the extractor doesn't grab right on the rim. There's a decent amount of room between the rim and extractor hook.