One Reply notes that there are actually eight possible outcomes of a 3Teamer, so getting back only 6x1 is a rip.
But Doug also correctly notes that if you make a single play at 11/10 and roll it over twice into subsequent 11/10 wagers, you'll come out at about 6.1
11>21>40.10>76.60
minus your original 11 and you're at 66.60
sounds a tad off barman, +596 is the correct payoff, often rounded to +600.