The voltage at the battery would not reach 14.4 (converter voltage) until battery is full --no voltage drop, no amps.
If the voltage is taken at the converter's terminals when the battery is connected, that voltage will read less just from being skewed by the lower battery voltage (they try to "middle")
Point being, if it matters for the Li just exactly where you are at for voltage, and you are seeing 14.2 instead of 14.4, that might need exploring. And what does the BMS "see" for the voltage it uses????
The Trimetric has a program for adjusting the voltage shown on its display if you want agreement between your battery voltage as taken with your meter at the battery posts and the Tri's display.
Solar controller's display voltage can be different again.
I don't know how fussy you have to be with Li whether any of that matters or if it is critical. ?