Is Fast scheduling jacked up at every store?

I'm using HD as my second job only two days a week and set my availability to 10am-6 on sat cause I have to work my full time job 4am to 9am. Five times in the last two months it has scheduled me at 6am on Saturdays. Has anyone had this problem cause I feel like an ass going in to the HR lady and asking them to change my schedule all the time.