Does The Setting Option "Log Rotation Size Threshold" Apply To Domain Logs (AKA Domlogs)?
Apache domlogs (domain logs - /etc/apache2/logs/domlogs/) are not rotated by cPanel main logging facility (cpanellogd) so the "Log rotation size threshold" option doesn't apply to domlogs. The domlogs are rotated by cPanel Statistics System instead. The only level of control that a user has on the rotation behavior of domlogs is basically through the tweak setting "Delete each domain’s access logs after statistics are gathered" which if turned off means the domlogs would just grow forever until something else that isn't WHM/cPanel rotates them and this tweak setting is not triggered by the size of the log files. So setting the "Log Rotation Size Threshold" option to any value (300 MB by default) would not affect the rotation behavior of the domain logs.