Several days agoe, I bought a brand new compaq c700 battery replacement, the spec as below:

the detecting sofeware BatteryMon shows that the capacity has lost 8.6%. The original capacity is 5200mah, now is just 4800mah available.It is hard to understand. Whether it is a normal phenomenon? Seeking explanation, thanks advanced!!!

Additional question:
I discharged the battery completly, then recharged it for 12 hr and rebooted it up, the capacity the computer showed is 4685mah, didn't reach to 4700mah any more. Did problems occured? I need answer urgently!