Help me do the math

I'm currently taking 7.5 mg Zepbound (pen). I'm debating on switching to either Refills (currently $507 for 3 mos) or Fifty410 ($499 for 3 mos). My issue is that Fifty410 has me starting at 6.75 mg and not 7.5 mg. I'm new to compounds so I'm not sure why the difference. I haven't done a consult with Refills yet so will my dose be the same there as well?

I want pure (no additives). My third choice was gimme care which is a little cheaper still but I'm seeing a lot of mixed reviews.

Any comments/suggestions appreciated!