First a reply for the OP:
I'm a recruiter at the kind of school you are describing and I only look at candidates with a minimum of 3-4 year IB experience, and 10 years of teaching experience overall.

And while I don't like to get in the middle of two dogs fighting:
I have looked at the most recent tier 1 list on the Member Forum with a colleague of mine who is a member and roughly 90% of the list are schools I would consider first tier and of the remaining ten percent more than half used to be. I have worked at one that used to be and I got out while the ship was sinking. Many in the field still call it tier 1 but I think it is no longer.
I have never seen a list of what qualifies a school to be tier 1 other than some vague notions on it having a high -but unspecified- salary and a few other things that were not quantified.
I haven't seen the PASS scoring system and we don't use a scoring system over here, so I am happy to not weigh in on that.

Thanks for the feedback!
Pretty much what I expected then.
I am a recruiter myself but have only worked at IB schools, and to be honest I also prefer candidates with at least 3-4 years of IB experience.
I have hired teachers with only AP experience for DP positions and usually it does take them a while to fully adapt. But AP teachers that switched to IB tend to say that AP is less challenging than IB. So I thought maybe American schools that offer only AP might not value curriculum experience as much, as switching from IB to AP is easier than the other way around from what I've been told.
He has experience teaching both CS and HL Mathematics and the rest of his CV is pretty stellar so I can still see him reach the interview stage. We shall see.

Asking for a friend of mine.

Are international American schools typically hesitant to hire someone who has only taught IB and not AP?

This concerns a top American School, so the kind that will have a lot of applicants and can therefore be picky.
Everything else on CV is top notch so only lack of AP experience might be something that they will mind.

Thanks!