Why does macOS show 100% battery and fully charged when "Charge Remaining" is lower than "Full Charge Capacity"
This is completely normal.

The numbers you see here should not be treated exact values - it is impossible to get exact values for the battery. The full charge capacity varies slightly with various factors - including, for example, the ambient temperature in your room.

The battery will ofcourse report a specific number to the operating system, but it would be a bad idea to expect the numbers to match up exactly. I.e. if you just charged until "Charge Remaining" matched exactly with "Full Charge Capacity" that wouldn't be a good strategy. This is why you see that systems from all manufacturers charge to somewhere "near 100%" - for example 95%.