I classified as salary but I read that if your hour change to work load you are not salary, example my schedule changes 3 times per year due to level of business. 13 weeks I work 48 hrs / 13 weeks I work 60 hours and 26 weeks I work 54 hrs am I stilled classified as Salary since I'm a manager

Not sure what country you are in, but in the US, yes, the number of hours you work can change every week if they want,

You are classified as salaried exempt if you are a manager and meet the exempt requirements no matter how many hours you work.

This would be true whether you worked 10 hours or 50 hours.

Shirley