In my opinion there are at least 4 reasons why, in the summer of 1862, these Parrot Guns were originally assigned to Etter's Battery and Harts Battery in the manner that they were.

1) lack of supporting equipment, limbers, harness', implements and other gear.
2) lack of proper ammuntion in general, and especially for training
3) lack of other organized batterys at the time, or experienced leaders to organize a new battery
4) lack of trained artillerymen to man the guns, or lack of trained artillerymen to train new recruits.

As I said after recieving the large artillery shipment in August of 1862 there was a wholesale reorganization of the artillery commands in Arkansas leading to the formation of several new Batterys. These Parrot guns were the best that either army had and it would seem out of character for all of these guns to be organized in just one or two batterys. The normal placement within an artillery battery would have been to have placed two of these guns (1 section) in a battery supported by two lesser grade guns such as Mountain Howitzers serving as flank guns. The flank guns would have been used to protect the Parrots Guns from Infantry assualt. This practice made it necessary for a battery to have at least two different type of ammunitions to service all of their guns and that could have been the reason that so many Parrots guns were assigned to Etter's and Hart's in order to preserve the small amount of Parrot ammunition that was available rather than divide it among several different battery's. At least it July 1862.