I’ve noticed something odd.
To the best of my recollection, every car I’ve ever seen with a rear center seat belt has a peculiar configuration. The receptacle for the center seat buckle is criss-crossed with that of the adjacent seat. What is the purpose of this practice? I don’t see how moving the anchor point of the seat belt one inch to the right or left could have any significant impact on its performance. And yet, manufacturers are apparently so concerned about this that not only do they print or stamp “CENTER” on the receptacle, but some of them actually key the buckles so that they won’t plug in to the wrong one.
It’s annoying to have to “cross the streams”. I’d like to think that this is somehow a matter of life or death and that the manufacturers aren’t just screwing with us. What’s the deal?
I will have to check but I’m sure this doesn’t apply to my car, nor any other I have seen here. Certainly didn’t on my Honda Accord.
I think it has more to do with how the buckle snaps together. They only go in one way, and if you were to plug it into the “plug next to the correct one,” it would cause a twist in the strap between the buckle and the mounting point. Any twisting on the strap would cause weak points. Weak points in the strap, if subject to an impact, could cause a failure.
I have noticed that the situation described in the OP is typical. I think the inch or two difference in the mounting does have a noticeable effect on how the belt feels to the wearer. Having the anchor point off to the side, rather than directly behind the hip, allows the belt to leave the hip at an angle rather than wrap around it (for people up to a certain size, anyway). I would imagine that the carmakers did some research on this.