Depending on the previous hole location there’s a chance they moved the jig forward 1cm to avoid the holes blowing out. That said if anything they should have gone back 1cm. +1 won’t make a performance difference but it might visually look off to you if you over think it. Also as others have stated it’s pretty common for factory markings to be off or just measured weird as fuck. I mounted a pair of prodigy 2.0s the other day at work and was surprised they had the “newschool” line at -5cm back from true center where I was asked to mount them.