Alright so as the title says, the 3x rings actually decrease your EXP
check this:
Without 3x ring
http://img29.imageshack.us/img29/3280/gunz018l.jpg
With 3x ring
http://img689.imageshack.us/img689/8413/gunz019b.jpg
DOUBLE CHECKED
Without 3x ring
http://img843.imageshack.us/img843/3236/gunz022.jpg
With 3x ring
http://img844.imageshack.us/img844/3949/gunz021v.jpg
Now unless its a graphical error [ the blue text misleads sometimes but the TAB is always accurate. ]
I killed her the exact same way twice.
fix your rings or give a refund if this is indeed the case with the 3x ring.