They did indeed hit more. Something like 69 were reported wounded. Sounded to me like the Army was aiming low so the wounded could crawl off under their own power. And the Egyptian Army does indeed have birdshot style anti personnel rounds such that it might not have required 69 actual shots. As soon as rioters start rubbing their sore spots they lose interest in bellyaching about pointless problems——amazing how that works.
Skipping birdshot off pavement to spread the pattern to hit the mob in the legs is an old street cleaning tactic. It can also break the momentum of a mob on the run (front ranks stumble or fall, tripping up those pushed by the rest causing a pile-up and blocking the street), and is what the striker and street sweeper shotguns were designed for.