Well, there are a couple of problems here, aren't there?
One is that the Jetting specs currently listed on the new Dr.D
site specify a "needle jet", and gives a part number of 5TA-14916-PL-00. To start with a needle jet would be a **-14947-**-**. A **-14916-**-** is a JET NEEDLE. The next problem is that the part number given doesn't come up as a valid Yamaha
part number. My conclusion is that it's a misprint. The number intended could have been 5TA-14916-LP-00, but that needle in #4 would be a step and a half richer. Doesn't add all the way up.
The second is that the only change recommended for extreme altitude is either a half step leaner needle or a 1 size drop in the main. If a 450 runs a 165 at sea level, 8000 feet should call for something closer to 158.
In any case, the info I cited is from the old version of the site, and is different from what's there now. Ask Ga426owner if you doubt it. (come on, you know you doubt it). I've also pointed out on a number of occasions, and provided references for backup, that the change to the NFLR results only in a 1/2 step change for the leaner, not a major change. It's fine tuning at best.
Doug Dubach recommended a combo of 165/42/ with an NFLR in #4 for nearly a year until the web site was revamped. He's free to change his mind at any time, of course, but given the established errors in the currently posted info, I don't think that's what happened.
Suppose you tell me why you think I made that recommendation.