Yes, however upon POR the initial SoC value is dependent on an OCV reading which can be inaccurate especially with less common battery types such as Li-Polymer. It takes time for the coulomb counter accuracy to take over and converge on the real value of the SoC. The expected error convergence is approximately half the error in half an hour. So, if your initial readings are off by 15% upon POR then after 30 mins it will be approximately 7.5% off and so on.
The M5 algorithm will be most accurate after a few discharge cycles, it doesn't expect the battery to be disconnected after each discharge. It is recommended to incorporate the fuel gauge into the battery pack if it is being charged externally.