This is a bit of an old topic but searching for 'plotomatic' on google this still comes up as the first post... So a bit of self promotion that may well help others interested in this plotting technique 🙂
I was always after an app that'd do plotomatic style scoring and the ones out there didn't look great... So I made my own... which I've also finally put on the app store.
Works on iPad only (should work even on old iPad 3's, def does on a 4) and I'm pretty happy with it - So check it out.
https://shootingcompanion.com/ or https://www.facebook.com/shootingcompanion
Obviously no electronics on point for the 'big' matches, but most clubs are a little more laid back.
Aside from the plotomatic side of things having my historical plots easily to hand to check things like my elevation has been really handy. I've also found in the wet that my iPad in one of those waterproof map cases has been better than paper.