As I said, I would always rely on the SOC from a Smartshunt once set up properly compared to a basic low cost drop in lithium battery. The other caveat is also that the system is functioning, if you have poor connections causing incorrect voltage readings then all bets are off. You still need to do some basic trouble shooting with a multimeter and basic trouble shooting on battery balance. If the battery is getting to >14.0V and <12.0A then it is full regardless of the SOC. If it gets to such conditions the battery SOC should reset to 100%. You need to be talking to your battery supplier.
MPPT
It is well accepted tjst the float voltage for lithium should be 13.5V which equates to 99 to 99.5% SOC to avoid long term.over charging. Discussed profusely on the web.
SmartShunt
Many of your current settings are not the default settings. Most of what I have described are the default settings or slight mods to these. The major difference is the charged voltage as discussed in the link below. Your current setting is the same as absorption and if there are voltage errors will not work.
GX device
Read the GX manual for a description of the DVCC settings and why they are useful.