Again this issue has been brought up!!
The Boeing flight crew training manual (B737) clearly states: the A/T ARM mode is not recommended. (CH 1.34)
On APP if A/P is off then A/T should also be completely off. Either all OFF or all ON.
No ifs and Buts. Airbus is a different kettle of fish, and should not be mixed with boeing.
Thats all.