I never said your cost analysis was incorrect nor did I even comment on it because I have not even taken the time to look at them yet so I am not sure why you are even bringing me into that. However, since you did, some of the numbers seem to be a exaggerated.
Going by real world fuelly mileage (which is 11 mpg for the 6.2 SRW and 14.5 for the 6.7L SRW), the 6.2L would use 5,455 gallons of fuel and the 6.7L would use 4,138 gallons in 60k miles. At the prices you stated(which are winter prices when the difference is greater) the fuel cost for the 6.2L $14,672.73 and $13,613.79 for the 6.7L. DEF usage would be about 83 gallons in 60k miles based on the standard 50 to 1 diesel gallon usage of most light duty truck diesels. At $2.90 a gallon at the pumps, that is an additional $240.70. So that would bring the diesels total fuel/DEF bill to $13,854.49 which is still less than the $14,672.73 pf the 6.2L. Although I will point out again that this is winter prices when gas is lower because refiners do not have add the special EPA mandated additives which make it cost about $.10-.15 more during the summer.
What I was commenting on was someone saying that the resale value between a diesel and a gas version of a 15 year old truck with 75k miles would not be significant. I checked for myself and the difference was over $4k which would mostly pay for the upfront cost of a diesel back in 2005.