Something does not seem right. Since this pack is already 'suspect' try giving it a 24 hour charge at a 'known to be accurate' 70 milliamps rate. That should guarantee that ALL cells reach FULL charge. Then discharge it and see what you get.

Also make sure the new charger is REALLY giving it the charge indicated. Maybe the charger is bad.

If you cannot obtain very close to full rated capacity after the 24 hour slow charge at the proper rate, throw the cells out. It just is NOT worth the risk you would take if you decided to use them. You have the right attitude: if you do not have 100% confidence in a battery pack, get rid of it. You will probably save a LOT of money in the long run.