Hey guys, I was searching for ink cartridges (specifically CZ638A) but at the same time, I came across CZ638AA (double As). I've tried searching the difference between the 2 to no avail, so I would like to ask the differences between the 2 models (CZ638A vs CZ638AA) both cartridges have number 46 on them..... Any help would be much appreciated ! Thank you for hearing me out !!!