Uhh, I'm not sure what you're asking, but let me try and answer it. So, to find perfect IVs with the judge function, it says "BEST".
So, a 5iv I believe means that there is an iv value of 5, or that there are 5 perfect ivs. So, if you are going with the first definition, then, the iv value of one stat of HP, SpAtk, SpDef, Atk, Def or Spe is 5. If the second, then they are the same thing. 5iv would mean 5 perfect ivs.