I work for bathfitter and the drain hole for our Acrylic liner is drilled in line with your existing tub drain so that the new drain component can be screwed directly into the old drain shoe. If it is possible that you are asking about the overflow hole, they do not need to be exactly lined up to the "T". they can be slightly offset without any worries. Your bathfitter installer take every effort to assure a good tight seal in that area of the overflow. As long as he/she can get the screws in to hole to hold the h-bar in place and sealed the area between the tub and liner with chaulk without an effect on appearance then all should be well.