General Discussion

The vast majority of refineries are fully continuous.
Crude goes in, cracking/hydrocracking, removal of undesired elements (mostly sulfur & other salts), reforming, distillation.
Diesel just comes off its fractionator stage after the -anes, gasoline, & kerosene are gone. After that there are heavier fuel oil, some lubricant oils & waxes (very little, but things like quartoventane), the tars, then asphalt.
So, the cost is distributed across all the cuts.
All that said, there is reason to be suspicious of diesel pricing. I think it's mostly because the overall yield as a % of crude is lower, but the demand is high. So, the price doesn't directly correlate to a smoothed out cost of production.