This is NOT a firewall test, it is a full HIPS test. There is a big difference.
Comodo Leak test don't even test many firewall network protocols it test mostly HIPS protection.
Privatefirewall and Outpost on default settings has advanced HIPS components disabled, so the reviewer should have enabled them.
They will get 340 on Comodo leak test if the HIPS components are enabled. I have tested it before.
TinyWall and ZoneAlarm doesn't have HIPS features therefore they shouldn't be expected to do well on a full HIPS test.
I found it kind of strange that UAC blocks Comodo leak tester which proves UAC would protect your system from leaks anyway.
Enjoy!!