It is probable that the cells are still balancing, but down in the 3rd &/or 4th digit, and the FMA (and others with limited screen space) have to round to two digits in order to display all the cells. What it is doing is continuing to charge the cells until the lowest voltage one is up to the cutoff voltage. In the meantime, if any of the other cells start to go OVER the cutoff voltage, it discharges them slightly. The FMA and Imax's are charging the cells in series. I imagine most others do, also.
As to whether it is OK to disconnect before the balancing act is done, the answer is yes. You are only losing a very small current - mine gets down to less than .1 amp during this phase - times a relatively short time - even if it lasts for 30 minutes, you only lose 50 mah by unplugging when the current gets down to .1 amp. This is the basis of Sid Kaufman's LiPo-dapter for field charging - that by cutting off when the total voltage is a certain value, you may not be "peaking" each cell individually, but you get to fly 95% charged cells 15 to 20 minutes sooner. Just be sure to do a complete balance charge when you get home and things will be sitting for a week or so anyway.