I finally worked out why friendly fire kickback and splash kickback were not working. The values for these settings are stored as floating point numbers between 0 and 1, while all the other friendly fire settings are stored as integers between 0 and 100.

Friendly fire kickback and splash damage kickback have been set to 25%. So now, when you hurt someone on your own team, you feel it - just not quite as much as the guy you shot.

Thanks to Tenaciousmojo for reminding me that kickback wasn't working.

Mojo also pointed out that on the player stats page, only the player's top 20 maps are shown. I bumped this up to 40.