Replacement Battery for Fuji X10 with mediocre endurance

I got myself this battery as a replacement battery for my Fuji X10, as it is much cheaper than the original battery. In use, I have the subjective feeling that the battery does not hold as long as the originals. This perceived weaker performance will be offset by the low price (emergency purchases you have to stop two - which together hold then longer than the originals in any case and they cost less anyway)