BTEC applied science

Hi! With mocks coming up and a struggle in one unit, I was wondering how how the grading worked on BTEC applied science. I want to get a distinction, I’m doing the BTEC extended certificate so I only get one grade. I am doing 4 units and I was just wondering roughly what I needed to get in each unit to achieve a distinction as I’m already achieving this in every unit but 1?? I’ve tried to use the grade calculator but I can’t figure it out. I was just wondering if anyone could help please!! Thank you