In the Gamecube Prima strategy guide it states the max saves is 12 and if you go over that the rank comes down.

So, I'm trying to get A rank in ClaireB but got:

Rank B
Time: 1:50 (way under what I wanted, 2:30)
Saves: 7
No first aids
No special weapons -- Did have to use R. Launcher Ada provides at final battle (boss simply would not go down with acid rounds or sub machine gun)

I've heard 3, 5 and 6 saves max...? What IS the number?

The official strategy guide was dead wrong.

Figured it out for the A rank, ClaireB, Gamecube version:

6 saves max
no special weapons
no first aid
time: 01:52:06

Gets you: S.Machine Gun, R. Launcher and HUNK game.

Edit!!!!!!!!!!!!!!!!!!!!!! Double posting is the bane of my existence.

I had the same problem, I was trying to get 4th Survivor and the Extreme Battle Mode.

Your play time seems good enough, for sure, also, make sure no first aids, and no special weapons. Most importantly, play on normal.