Not enough mAh....help!!

[Mike.L]

Me and sylvester have have just recived new batteries and have problems with charging them to full capacity. For instance my batteries are gp3300's and only charge to around 2500-2600 mAh charger settings are at:
NiMH,3300,3 amps or auto,and the peak is 8mv/c.

Sylvesters are ib 4200's. We both have the same charger. His settings are:
NIMH, 4200, 3 amps or auto, and the peak is 8mv/c.
After each charge both our mAh would decrease.
and his would reach: 1st charge: 3300MaH 2nd charge 1900mAh 3rd charge 1100 mAh

our chargers are: Duratrax Piranha AC/DC digital peak charger, normal NiCD and NiMH.

you can look at the charger here:
http://www2.towerhobbies.com/cgi-bin...&I=LXCLD5&P=ML

what seems to be the problem?? our run times are decreasing my the charge!
HELP