That's a pretty good guide.
I tell hunters to try one of two shots, depedning upon the opportunity:
1) most deadly, IMO, is to shoot the pig in the brainstem, and break the spinal column, at the level of about C5 - C 6. This would simply be about 2-3 inches horizontally aft of the ear. You have about 3-4 inches of "vital zone" margin of error here, as a good bullet will still break the neck if a little high, and sever the carotid artery, if a little low. Paralysis of the entire body down will occur if the neck is broken, and the brain can only survive for a minute or two if the carotid is severed.
2) Low on the shoulder. The Scapula is thinner at the bottom than the top, and the heart sits right at the crease of the axilla (analagous to the "armpit" ) Anywhere you hit the animal low in the shoulder will get the lungs and / or heart. This shot carries a lower % ratio than # 1, because heart shot hogs can still run 100-200 yards, and it just hit in the lungs, might go miles.....believe it.
Edit:
While I don't recommend it, while driving around the ranch, I have shot hogs with .22 LR, low in the crease behind the shoulder (right in the heart) and watched them run out of steam in about 175 yards, then lay down and die. (this area is very soft and actually relatively unprotected, which is why "dog hunters" can knife them there). Sometimes you run across them, when you expect to see a Skunk : /