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Jeff
The OP mentioned "half-synthetic" oil. I haven't seen "semi-synthetic" on the market for m-c oil but it is widely sold for cars. You should know that "semi-synthetic" is a blend of petro and synthetic, as you would expect, but there is no standard for the percent of each in the blend. Oil with just 10% synthetic could be sold as "semi-synthetic".
For what my opinion is worth (not much, my wife would tell you) I will be switching to full synth at the up-coming 12K service on my 2011 RT. Then I feel comfortable with 6K oil changes and hot and cold ambient temperatures. Been using it in my Honda car which has 10K oil changes. If I spent $20K on the vehicle, the price of motor oil is insignificant for 6 or 10K.
pete
I remember discussing this when we had to make a decision in our auto shop. The Shell/Chevron/Motorcraft/Etc. distributor explained to me they could not call an oil semi-synthetic unless it had at least 14% synthetic oil.
The manufacturers of oil use two grades of oil, class 1 and 2 if I remember right.
To get to a certain API rating they could use straight class 1 or use class 2 and add enough synthetic to bring it up to the specific specification they were shooting for.
That's the way I remember it anyway.