When output volume increases, do variable costs per unit increase, decrease, or stay the same within the relevant range of activity? When output volume increases, do fixed costs per unit increase, decrease, or stay the same within the relevant range of activity? Apple produces tablet computers. Identify some of the variable and fixed product costs associated with that production.When output volume increases, do variable costs per unit increase, decrease, or stay the same within the relevant range of activity? When output volume increases, do fixed costs per unit increase, decrease, or stay the same within the relevant range of activity? Apple produces tablet computers. Identify some of the variable and fixed product costs associated with that production