It's nice that the Solar charge controllers can set the upper absorption voltage to 69.56 volts.
For LiFePo4 cells that would allow 20s (with a corresponding tail current setting).
However with 20s LiFePo4 the cells will stabilize to 3.37V/cell after some resting time, that is 67.4V in total.
It would be great if the Multiplus and EasySolar inverter upper voltage limit will be slightly lifted from 66 to 68 (or 67.5) volts.
PS An even number of 20s saves the hassle and dimensional inaccuracies when inserting a dummy cell in the 9s row to match the row length of 10s (between the pressure end plates).