Hi Cory,
I believe that there are several reasons why this occurs.
You will find that the HA will quite often attempt to place the arms design within the heraldic jurisdiction and time period from which the client's original ancestors came.
It may also be at the request of the client to do it in a specific way that is similar to other arms granted in that surname.
It is also a quirk of HAs to try out something new that may be more of a challenge to them in their work, thereby lessening the tedium of doing all arms representations exactly the same.
You might find that there are other reasons which may also be contributed by some of the other AAH HAs and Heralds.
Rgds,

PS: it's AAH not AHH ~(;-))