New weather striping will be stiffer than the weather striping you replaced and have a more pronounced cross-section. This will allow the new weather striping to conform to the door contour. Also, a slight adjustment of the strike plate at the jamb will help. If not, I suggest shutting and latching the door. Over time the weather striping will weaken slightly and conform to the door, thus ensuring a good seal and secure latching. A few hot, sunny days will accelerate the process. Good luck with your project.
