Is it an appropriate comment to make that one way to improve profitability is to increase volume sold, because as gross profit increase, client will improve their profitability in the operating margin level, provided no incremental increase in fix cost with additional volume sold.
Of course this is on top of the option to increase price and cut down costs
Now, if you consider only average margin, you have an additional option, which is to stop selling lower margin products. If you remove products whose contribution margin is below average margin, then your margin will go up. Unfortunately, your absolute profit will go down. I don't see why a company would want to do that...