battery revision

the battery size is 4110 and cell revision is 3933. what is that difference between them why???

Battery Information:

Model Information:

Manufacturer: SMP

Device Name: bq20z451

Pack Lot Code: 0

PCB Lot Code: 0

Firmware Version: 901

Hardware Revision: 1

Cell Revision: 3922

Charge Information:

Charge Remaining (mAh): 3956

Fully Charged: No

Charging: Yes

Full Charge Capacity (mAh): 4194

Health Information:

Cycle Count: 49

Condition: Normal

Battery Installed: Yes

Amperage (mA): 1184

Voltage (mV): 12950