Why did my PR go down? (in General)

Strange, Skucum just got his VB and Compound back from the Blacksmith and his PR went down slightly.

Before:
Power Rating: 64,111
A Vorpal Blade [75x16] (+10)
A Compound Bow [5x15] (+9)

After:
Power Rating: 64,096
A Vorpal Blade [75x17] (+11)
A Compound Bow [5x16] (+10)

I didn't train or fight or move any equipment around during that time. Nobody attacked me either.
Anyone care to speculate why that happened?

a miracle.

Did you train? I'm sure your weapon allowance changed, but I don't know how.

so basically it's off by 0.007%?

who cares?

That has happened to me before, when my weps added PR, and when I unequipped and equipped then again my PR would fall..

Oh god, this is a tragedy! Some body get the defibrillator. Please NO ONE panic. Does anyone know CPR? /me crack under pressure WWHHYY?!? /me brakes the news to sukotto Sukotto, you lost 15 points of your PR. Im sorry. /me breaks down and cries after experiencing such a great loss

Oh god, this is a tragedy! Some body get the defibrillator. Please NO ONE panic. Does anyone know CPR?

/me crack under pressure
WWHHYY?!?

/me brakes the news to sukotto
Sukotto, you lost 15 points of your PR. Im sorry.

/me breaks down and cries after experiencing such a great loss

sorry for spamming.

settle down, he's not freaking, he's probably HAPPY. lower pr = better rewards.

He's just curious.

Jon: I'm not worried about it, just curious.
Tony: chill dude

You make a post about losing 15 points of pr and your telling me to chill?

Tony, stop being a jerk.

He upped the NW of his items and his PR went down, he is curious.

this is a result of your weapon allowance going up...

I thought weapon allowance was something like:
- first 2/3 of the weapon's net worth is ignored
- last 1/3 of nw is put toward your pr

So I wonder why my pr didn't go up when my weapon's nw went up.
Perhaps the pr calculation is not precise and it's just my good luck that it wasn't a higher number?