i believe they use a Vocorder (sp?) which is different. it doesn't control the pitch of his vocals rather process them. i know that is what they used on Focus, but not sure what advance technology allows them in 2008-9 when recording this.
Technology Neil Young was using in 1982 on his Trans album.
In my line of work, AutoTune means automatically tuning in to whatever navigation radio frequencies are needed to keep the plane going to the right place. So I'm cool with it being used in metal.