His analysis is based on a requirement of 3 turnovers per day, which we do not agree with.
His single speed pump is designed for 100 GPM at 10 hours per day and is about a 2.25 HP pump.
This is a poor design for a single speed pump.
If you only need one speed, you can use a much smaller pump that will do about 30 to 40 gpm.
IN any case, a VS pump is usually the most efficient choice, but his analysis is seriously flawed.