To for the center of the 'A' there is a post that creates that void. When the post breaks off the coin, then it will be different looking. If a total break off it will show a void. It is breaks off below the base, the it will rise above the device.

Note the posts on these broke off below the base of the device, leaving a void below where the post was. Thus the void creates a riser taller than the post itself. Note this on these two examples posted. On a doubled die on the quarter reverse design, all the devices could be enlarged:

Note compared with a normal die, how much the devices could be enlarged.
Here is a closer view of the spread and enlargement of this
DDR's examples:







So on a doubled die, the devices will show a spread/enlargement on the centers of the devices. Some devices will show notches. But on the outside edges there will be no reduction of devices/contour, unless you have a doubled die with
Machine Doubling. Most of the time it is just MD on a normal die. So look at the centers of the devices to see if they are larger than normal. If you look on the outside edges of the devices, it is a waste of time as that is where you will find the common
Machine Doubling that are not doubled dies. Look at the centers of the devices, no spread, move on to the next coin. (keep looking and you will find
Machine Doubling)