waton, I was thinking the same thing
"Listener. : and not to forget that this time in the presence of unbaptized persons in counted as "service time", by both parents, as part of the 10 minutes + that every human on this planet receives each year."
jw parents are only allowed to count 4 hours each month (4 hrs/dad; 4 hrs/mom). If there are now 2 trips roundtrip to the KH each week, 4 one-way trips; 4 weeks x 4 = 16 trips x time it takes to go one-way to the KH, (10 minutes is quite short let's make it 20 minutes), 16 x 20 minutes =320 minutes divided by 60 = 5+ hours. Thus the parents don't have to have a real study at all with their children, but can only count 4 of the 5 hours.
I can see lots of ways of expanding this time. In my observation and those of the elders, maybe 10% of the families have a formal study with their children.
Singing would be a win win situation.