One more tip for you based on the steps you mentioned in the discussion:
Do not allocate hours for a resource in the team or assignment tab and then change the Display Type to percentage. That will create a huge confusion in your calculation.
Considering your case itself, adding 40 hours per week means 100% allocation for a resource, assuming you have 5 working days with 8 hours each.
But the moment you are changing the Allocation Display Type to Percentage, it takes all the values as Percentage, and if you do not correct the same 160 hours will be denoted as 160%, which means you are over allocating the resource Big Time.
Hope that helps.