I won't speak on behalf of OP but I can tell you about my frustration with PTCAS' limit of 4 references.
Firstly, each DPT program has their own set of requirements applicants must meet, including LOR requirements. A variety of programs ask for 2 physical therapists or 1 physical therapist or 2 professors or 1 professor or 1 professor from the sciences or 1 professor from your major or 1 health care professional or 1 employer or some nonsense like "someone who can speak to your management and organizational skills", etc. If applying to multiple programs, it literally becomes IMPOSSIBLE to satisfy all of the schools you are applying to because 4 is simply not enough. Perhaps 6 would be feasible.
Secondly, is a personal frustration. I have formed the closest bond with a non-science professor, yet I am pressured to not ask her for a letter of rec, because I am limited to only 4 letters. I have to be choosy and perhaps ask a professor from my major (whom I have a decent relationship with but certainly not the best) in order to better satisfy more schools. But in being choosy, I am sacrificing the quality of the LORs I will be sending to schools (WHICH OBVI SUCKS!). This could all be simply resolved if PTCAS would allow a greater number of LORs to be saved in the system. This brings me to my next point.
Thirdly, why is there no option to specifically choose which LORs we would like to send each school!?!? They do this for medical school applications. Why not PTCAS? This way I am not "overworking" admissions committees by making them read 4 LORs when I'll just send them the 2 or 3 (out of my saved list of 6) that they specifically requested? PTCAS should allow us the option to delineate LORs to specific schools to both convenience the applicant and admissions committees.
End rant.