Mp3tag does not do this calculation for track value automatically.
Mp3tag may report and display Replay Gain values but it does not analyze audio data to calculate track value or any other value associated with Replay Gain.
Replay Gain is metadata, and Mp3tag can edit it, but that is done by user input and not by analyzing the audio payload.
Even if you knew a formula to make the calculations, it would normally require knowledge of the audio waveform and that is not available via Mp3tag.