One of KL's strongs is being one of the most punctual airlines. Amongst others, this is closely linked to a clever and flexible fleet deployment system. It also means that aircraft deployment changes a lot. Since there is a few month delay in seat deployment, this also extends the seat roulette with a few months.

Since this is a day flight, I wouldn't change bookings around, and risk the slippery slope seat. However, if it were a night flight, the new seat would become a very important parameter in my decision process...