As others have stated, the pump does 3 things for you ... filters the water (at any speed), creates skimming action (at some minimum speed), and enables chlorination of the water (due to your in-line chlorinator).
Ideally, you would be able to set a VSP to run at a low speed most of the time (for water filtering) and then kick up to a higher speed on a schedule (for improved skimmer action), through automation. This gives you the best energy efficiency, while still meeting the 3 goals. I personally have my VSP scheduled to run 1200 RPM for 24hours, and then also have a schedule which kicks it up to 2500 RPM twice a day, for one hour each time (8-9am and also 7-8pm). This keeps my water crystal clear, skimmed well, and enables my SWCG to produce chlorine all day. Given my local electric rates, this costs me $0.30 a day to run line this, so less than $10 a month, or roughly $110 a year in electricity.
But based on this picture you posted, it appears your pump doesn't allow scheduling different speeds for different times of the day, and is limited to a single chosen speed, for a set # of hours
Seeing as that is the case, I would say your best bet is to run it at the lowest speed which creates good skimming action, for the minimum # of hours required to keep the water clear and the FC level in range.
What is your pump's model number? I wonder if you could buy a different control board for it, so you can take full advantage of the variable speed capabilities ....