F-350 Tow Rating Same for 3.55 & 4.10?

Am I reading this right?

For an F-350 DRW 6.7L V8 Diesel 4x4 CrewCab 8’ Bed, the 5th wheel tow rating is effectively the same for both a 3.55 axle and a 4.10 axle? 27,300lbs vs 27,500lbs? That does seem right.

http://webcontent.goodsam.com/trailerlife.com/digital_editions/TrailerLifeTowGuide2017.pdf

Page 21, Top left.

The Ford towing specs for a 2017 F350, dually, diesel, crew cab, fifth wheel are the following:
3.55 ratio, 27,300 lbs.
4.10 ratio, 27,800 lbs.

It also stated that the tow rating is limited to the 5th wheel hitch rating of 27,500 lbs. I'm assuming that is for the factory ordered hitch.
These figures are from the Ford web site.

F-350 Tow Rating Same for 3.55 & 4.10?

Yeah, that seems weird. I would think that gap would be wider. So I’m going to tow a 5th wheel, what’s the benefits of getting the 4.10 gearing other than the extra 500lbs? The 3.55 puts you at lower RPMs at highway speeds and gives you better MPGs. Usually you go for the higher axle ratio for the power, but if that’s not the case here, I don’t get it. Am I missing something?

Higher axle ratios are not for more power. 4.10 is lower than 3.55 not the other way around.

I had trouble deciding and on the Ford forum a guy answered me with the speeds at different RPM's for each gear range.

4.10 DRW
4th gear 55 = 2764; 60 = 3015
5th gear 55 = 2061; 60 = 2248; 65 = 2435; 70 = 2622
6th gear 55 = 1624; 60 = 1772; 65 = 1919; 70 = 2067
Sweet spot for climbing: 64 - 75


3.55 DRW
4th gear 55 = 2393; 60 = 2610; 65 = 2828
5th gear 55 = 1784; 60 = 1946; 65 = 2108; 70 = 2271; 75 = 2433
6th gear 55 = 1406; 60 = 1534; 65 = 1662; 70 = 1790
Sweet spot for climbing: 55 - 64; > 74

Since I am always towing in the mountains since I live in East TN., he also included the sweet spot for climbing which he had as 2400-2800 RPM, which agrees with horsepower curve. I went with the 4.10 and for my 16K fiver, it is really overkill. But, I am glad I did. Truck stays in 5th in mountains running 60-65, and I like the ability of the 4.10's acceleration. From what I have saw with posted MPG's from 3.55 drivers, towing is about the same and they get a little better not towing, less than 1 MPG.