|Found this in /var/log/daemon.log:
/usr/lib/pm-utils/power.d/intel-audio-powersave false: success.
Running hook /usr/lib/pm-utils/power.d/journal-commit false:
/usr/lib/pm-utils/power.d/journal-commit false: success.
Running hook /usr/lib/pm-utils/power.d/journal-commit_orig false:
Setting journal commit time for / to 0...Done.
Setting journal commit time for /mnt/REVODATA to 0...Done.
Setting journal commit time for /mnt/WHATEVER to 0...Done.
The file "journal-commit_orig" is just the backup of the original file, before I changed the default for AC mode to 120 seconds. So this being done by ACPI, right?
FIXED: The backup file "journal-commit_orig" was apparently being parsed, after the "journal-commit" file, and the value "commit=0" was accepted and used. I deleted that file entirely, leaving only the edited "journal-commit" file, with the commit value changed to 120, and after a reboot the ext4 filesystems are mounted with the desired options, according to "mount".