Without the quiz factor everybody plays bar/20/16 and doesn’t give it another thought.
The QF leads one to look at bar/21, 13/8 and the more you look at it the more attractive it becomes.
The 8-pt would be very useful for Blue so slotting it is good. White has only 8 checkers in the attack zone while Blue has a four-point board. Now is the time to take a small risk. An exchange of hits will strongly favour Blue and not White. So much so that bar/20/16 is actually a blunder.
Needless to say, I got this wrong over the board and then XG was kind enough to point out my error! Bar/21, 13/8 wins the same number of single games as bar/20/16 games but 5% more gammons.