In my last 8,553 Hands at $25NL on Party I've won $609.33 and it says my BB/100 is 14.25.

Calculation:
BB/100 = [$609.33/(8,553/100)]/$0.25 = 4 * 609.33/85.53 = 28.50

Why does my BB/100 say 14.25???

It does the same thing for Prima.

Does anyone else experience this?