While I don't think two nock points a re necessary, it is cheap insurance whether shooting split or three-under. I've seen some pretty convincing slo-mo video of an arrow nock sliding down the string at release. Just can't imagine why it would matter which finger is under the nock. Once the string's gone, it's gone. That said, I now use two nock points tied out of B50 waxed string material. Couldn't be easier, but one video is worth a thousand words. Do a search on here or Youtube for "how to tie a nocking point". The one from SBD string guys is a good one.