Importance of the constant voltage charging of li-ion
If you use CC until Vcell is ~= 4.2V then.


Cell capacity will be about 80% of maximum
Charging time will be about 45 minutes.
Cell whole of life capacity stored and recovered will be signifixantly higher due to the gentler charging cycle.


4 hours should be very adequate for a full charge at I max = C.ie Imax =~ 3.2A for 3200 mAh cells. The CC stage will last about 45 minutes leaving 4h-45m = 3h-15m for the CV stage.

If you search SE EE for LiIon charging you will find this area is well covered.