Smuge,
My uninformed guess would be more along the lines of- it was a structurally more simple installation without the need to reposition Nav lamps and other things. and could be accomplished quickly.
I will have a chat with their chief aerodynamicist of the era next week when I see him. perhaps he can shed some light.
When I was challenged to fit MAWS sensors to a jet, I found a very simple solution to the forward facing ones. Cable runs dictated a few constraints.