First of all, the question was phrased in a way that I took it as assuming said cockpit as being intended for an observer, not the pilot. As to the offset location, I can only offer an educated guess. The Loire 130 (and I assume its intended successor the NC.420) had a secondary liaison role and was capable of accommodating up to four passengers. Putting the cockpit on the port side would place all left hand side controls, trim wheels, etc on the fuselage wall, leaving the rest of the forward compartment free for passenger seats and/or small cargos. In addition, this layout appears to emulate the usual pilot-to-port arrangement usually found in multi-engined aircraft. But I repeat that all this is plain guesswork.