the idea of shooting towards the p[elvic/legs takes me back t o kickboxng classes. general rule in Thaiboxing is if you take your oppenents legs out they cant fight. shoot someone int he hipsd or in the legs they are gonna drop. plus shooting down means missed shots are goin t hit the ground not someone standing behind the BG.
This was long advocated by Jim Cirillo who had been in enough gunfights and put the practice to use to be listened to seriously. Mind you he had also taken head shots when needed. This was as a part of the NYPD Stakeout Squad where he killed too many criminals to be promotable in the super liberal mayor era.
The pelvic region is critical to remaining upright. If shattered you go down no matter how dedicated you are to continuing the fight. There is also significant pain in striking that region, it is often left unprotected by body armor and is easier to hit than a head in a gunfight. The pain though may be a non-issue if the failure to stop is due to drugs or psychological state. Finally, holding your aim on that region allows one to observe the hands of the person they are confronting, a big plus for a LEO holding a suspect, compared to holding COM where the hands are obscured. Remember, hands kill.
The problem is that the bones in the pelvic region are incredibly strong and hard to bust with a pistol round. The Stakeout Squad often used shotguns and M1 Carbines, both of which would get the job done, but the handgun rounds could not be certain of doing so.
One thing is certain. If the shots on the COM are not having the needed effect then hitting the criminal in either other place, head or pelvis, is certainly better than not at all. I think both practices are worth consideration.