I think it's a lot easier to play some of his tapping riffs, being able to go down an octave, instead of shifting to a higher position on the neck. Take these 2 videos as an example:
Bloodmeat tapping on 4 string:
http://www.youtube.com/watch?v=Pn7uvl_tgog
Bloodmeat tapping on 5 string:
http://www.youtube.com/watch?v=vlduiVhANn0
It's tough to explain it to you without showing it, as I'm really wordless when it comes to things like this, but if you watch and compare those 2 videos, and his hand positioning, you'll basically understand it.