Hi,
the settings are in includes/misc-functions.php
lines 76, 77, 78 and 107, 108, 109 have code that looks like this:
‘ROUND( ( ( b.avg_star_result * b.avg_count + count_entries * star_result ) / ( b.avg_count + count_entries ) ), 2) AS adjusted_star_result’;
For each of the results “types” change the ) ), 2) to ) ), 1) (the number after the comma is the number of decimal places).
I have no idea where you could put this as an over-ride code to prevent updates changing your new settings.
cheers,
Fred