Can one employee in a department of 25 be held to a different attendance policy then everyone else?

I am a non-exempt employee who works in a department where everyone else is exempt. I have been here for 5 years. I have adult ADHD, which affects my time management and organization on a daily basis. I arrive 15-30 minutes late to work at least once per week. I have never been written up in the 5 years that i have been employed with my organization. For 5 years, my boss used her own version of the attendance policy. She has never had to use write-ups or verbal warnings. In January 2018, my director gave me a counseling on my attendance and gave me a copy of the hospital's attendance policy that counts occurrences. She informed me that she would be using the occurrence policy from now on. No one else in my department is supervised via the hospital occurrence policy. She explained to me that she could hold me to the policy because I am nonexempt and everyone else is exempt. I feel signaled out despite the fact that I take full responsibility for my lateness. Can you let me know if she has the right to give me occurrences when I call out or when I am late, and not give others occurrences when they are late or call out. I am applying for disability accommodations and pray it is approved.