Right now, a crew cab F250 is cheaper to buy than crew cab F150, roughly same options, if you go build and price them on the Ford website.
If you price a heavy duty payload package F150 (naturally aspirated with the 5.0), and compare it to a similarly equipped F250 with a 6.2 engine, the F150 is higher. The payloads are very similar, but higher on the F250 by about 4-500 lbs).
If you don't add the heavy duty payload package to the F150, then it's not really a fair comparison. Non-heavy duty F150 has a really low payload compared to the F250, so that's not really a fair comparison.
If you add a 3.5 L EcoBoost engine in, the price differential goes even higher, since that's a premium engine. You can't get the heavy duty payload package with the 2.7 L Ecoboost or the base V6, only the 5.0 and the 3.5 Ecoboost.
Expect that price premium to apply to the Super Duty when the aluminum body comes to those models as well.
2016 F250 CCSB 4x4 6.2L
2001 Lance 820