The schedule is largely dictated by the teams and not the league.
The Greyhounds choose to play 3 road games in 4 days because of the travel schedule. Take for example November 21st-24th where they have to play in Guelph, Sault Ste. Marie, and Owen Sound in 4 days. That's possible but not reasonable to do in 3 days.
Teams with easy travel schedules choose to bunch games on the weekends for financial reasons. You'll notice that each and every one of Kingston's 3 in 3s are Friday, Saturday, Sunday.
Rest assured, the league isn't handing out any favours.