Anybody plateau with minoxidil?

Just as the title states. I've been on minox since the beginning of the year. I took a month off because was too busy/lazy while studying for exams. 10 months in, it seems like it's hit a plateau and doesn't seem to be as effective anymore.

Contemplating of adding Propecia to the regiment to the exisiting 5% Minox + Nizoral + T-Sal shampoo.