First, it is unlikely you'll safely make the runway in the case of power loss mid-downwind, no matter what your spacing.
Isn't power of 180 landing a part of FAA commercial pilot practical test standards for ASEL, which all CPL applicant have to demonstrate.
The applicant must land the aircraft within 200 feet of a point on runway abeam the point in downwind where the engine failed.
If one can do it at the end of the runway, you can do it at the middle of the runway.
Millions of pilots have demonstrated and passed the Power of 180 accuracy landing from traffic pattern.