Interestingly enough someone decided to do a "test" of Kirkers claim on the adhesion of their primer over ospho treated metal. Here's a 2-part video (not mine) that shows the results.
Ospho and Kirker Primer Test Video - Part 1Ospho and Kirker Primer Test Video - Part 2Appears that the adhesion claim is good. The testing methods aren't what I would call being done in the safest manner

, but the results of no adhesion loss kinda gets the point across.
Thanks for sharing the Kirkers product knowledge on this topic KENC!

Dan