Becoming AGI then CFII

Hi. If I want to become an AGI and then a CFII, do I really have to
take these 5 exams:

1) Fundamentals of Instructing
2) Ground Instructor Instrument
3) Ground Instructor Advanced
4) Flight Instructor Instrument Airplane
5) Flight Instructor Airplane

I understand that your AGI ticket covers your FOI for the CFII ride,
but do the Ground Instructor Instrument/Advanced tests not cover your
for Flight Instructor Airplane and Instrument Airplane? My
understanding is it's mostly the same material, so worst case you're
just taking duping tests somewhat, right? But do I have to pay $80 *
5 = $400 for what's really 3 tests? And is there any time limit on
the validity of the knowledge exams like the 24 month limit for
Private/Commercial?

I was hoping I could take #1-#3 and then use my AGI ticket to cover
all the knowledge exams on the CFII checkride but it appears now.

If you're wondering why bother with AGI when I'm shooting for my CFII,
I like the idea that it never expires.

Any tips appreciated -- thanks!