Why does the capacity baseline matter when reading a health estimate?

The denominator matters. Comparing current usable capacity with original gross capacity mixes two different boundaries and can make apparent degradation look larger than it is.

Use an original usable-capacity figure that applies to the exact variant and a compatible current assessment. Record the sources rather than assuming a battery badge supplies both quantities.

If the baseline cannot be verified, leave the capacity-retention calculation unresolved. Showing unknown is more useful than giving a precise percentage built on the wrong specification.