On iOS17 and watchOS10, the BatteryPhone's remaining battery power is displayed in 5% increments.
This change is due to an internal change in iOS and watchOS, and there is no way for developers to do anything about it.
Actual and displayed battery amount
100%~98% 100%
97%~93% 95%
92%~88% 90%
87%~83% 85%
~~~
Depending on the timing, this may cause the battery level displayed on the BatteryPhone to differ by 5-10% from the actual amount.
Thank you for your understanding.