^and to add, daystocome is actually completely right. only a n00b shop tech doesn't measure the lines himself, the line already made into the topsheet is part of the graphic and therefore can be printed wrong easily when the topsheet is put onto the ski. it's called being thorough.
example: the thall topsheets from last year were almost all printed forward of the actual mounting position. a shop in crested butte mounted tons of pairs 1cm forward of center because of this issue, something the tech should've figured out after doing the first pair but nope. never trust the mounting lines on a ski that is mass manufactured (the case is different for example with on3p skis, we love mounting those at the shop I work at since every single measurement is exact to the nearest mm, haha)