Coffee, now I'm really confused. Ford is claiming that the "ignitor" tick is "solved" by the additive, not by lash adjuster replacement.
It may be that, when the dealer describes the problem to the hotline, they can't tell for sure which problem you have -- and the dealer doesn't know the difference. So, the engineer will listen to be sure and decide accordingly.
I'm betting they go with the additive, since that's the cheaper solution.