Actually it is exactly 11 weeks between both of these litters.
11 weeks would be 77 days. A August 26 birth date would leave 5 days in the month. September adds 30 more days, October adds 31 and the 11 days of November makes the total exactly 77 days.
According the the meerkat life cycle information on fkmp, which is free information http://friends.kalahari-meerkats.com/index.php?id=lifecycle gestation period is 10 weeks (70 days)....and yes like rrosser said bother are Flower's litters...