Total fixed costs remain the same, within the relevant range. However, the fixed cost per unit decreases as production increases, because the same fixed costs are spread over more units.

What does the relevant range apply to?

The relevant range refers to a specific activity level that is bounded by a minimum and maximum amount. Within the designated boundaries, certain revenue or expense levels can be expected to occur. Outside of that relevant range, revenues and expenses will likely differ from the expected amount.

Does relevant range apply to fixed and variable costs?

Relevant range is a level of volume or activity within which a company is expected to operate. ... Fixed costs may not be fixed and per-unit variable cost may not be variable outside the relevant range of activity or volume.