The MAX17055 as well as other ModelGauge m5, ModelGauge m3, and ModelGauge products do not require that the battery be full charged or discharged to maintain fuel gauge accuracy. The accuracy will depend on the model loaded, the fuel gauge used, and the battery chemistry. Figure 2, page 12 of the MAX17055 datasheet shows some performance results for ModelGauge m5 EZ, and is shown below.