[General] Codec question (just bought G729)

Hi, I'm using CSipSimple with Voip.ms on Android. I bought G729 so does that mean I should disable the other 8 codecs that are already checked? I would normally assume so, BUT 4 of the 8 were under the tab "slow codecs" which makes me wonder if there's a special reason for keeping them active which I don't know about.