I'm not sure what your actual question is.
The highest "slope difference" there is 10, which is less than a 9% difference, AND it's the slope, not the course rating, so you're talking about multiplying a differential by either 0.89 or by 0.83. Not a big difference.
So what's your actual question?
I think I figured it out, and emailed back. There was a second accounting for the (CR-Par) term, which caused the discrepancy.
I believe the old system simply truncated the calculated course handicap, always rounded it down. As you said, now its simply rounded, with 0.5 rounding up. But now that we're not using slide rules, we can carry enough significant figures to tell the difference between 0.49 and 0.51, retaining a little more precision than we once did.
Again, when allocating strokes to individual holes, the recommendation is to go off the low handicapper, so nobody is ever having strokes ADDED to his score. This is never an issue with stroke play, the Plus handicappers get strokes added to the total score, but when looking at individual holes, its best to start counting at zero.
This is one interesting thing about the new terminology. Course Handicaps are always used in calculating Net Double Bogey for maximum hole score and Net Par for holes not played. Playing Handicap is used in a competition to allocate strokes. Beyond adjusting for match play off the low ball, Playing handicap may also be reduced from the Course Handicap by some percentage, depending on the format of the competition, as indicated in Appendix C.
Why didn't you just say this in the first place?
When handicap reporting is off and it's in the off season, no one cares. Use a handwarmer if you want. You'll still be dealing with mud, plugged lies, casual water, wind, drizzle, temporary greens, and other slop that will overpower your heated golf balls. If you want to play in sub 45 degree weather more power to you.