Migrant Worker, reducing my hours from 20 to 16

Hello. I have been deemed as eligible as a Migrant Worker for student finance. Before the academic year, i am working overtime hours, even though my contract specifies i am contracted 16. When i start my course, i plan on working these hours. My payslips show my overtime salary, even though I sent the evidence for my contract. Would it be fine if i worked those 16 h then?