I
was getting donuts every 120 balloons popped. Then the Monorail event started and they stopped. I asked around about it and was told that the number had changed to 300 balloons plus a 1% chance of getting them at random.
I re-computed when I should get them based on 300 (without a reset of my previous total) and came up with October 11th. Then Monday (September 21st) I got 5 donuts in my Android game... Then popped the balloons in my iPad game and got 5 donuts there, too - even though the games had been 30 days out of sync.
So I don't know what's going on.
Then there's this thread
http://forum.ea.com/eaforum/posts/list/10360896.page about Mystery Box prizes where everyone is getting either 10 donuts or the Itchy & Scratch Billboard in their latest Mystery Boxes (I got the Billboard in my iPad game and the 10 donuts in my Android game).