An off topic observation to share that I thought might be useful if this thread comes up on a Google search in the future...
Qatar allows for exit row seat selection for OWE at time of booking while MAS only allows at check-in time.
I was looking at Qatar operated, but MAS codeshare ticketed flights and was unsure which policy would apply...and always a major consideration...what the system actually allows you to do.
Surprisingly, I was able to select exit row/ extra leg room seats for free on the MAS website for the QR operated flights.