I just upgraded to v3.4.89 and noted the resulting file size for calibrations is about half.
For years, I've used HPT to calibrate a 2001 Camaro w. 3.8L V6. Up to now file size was 466-467-KB. I've done two cal files with v3.4.89 and both are 234-KB.
What has changed in the application to make the tune files half the size they were at one time?