It seems that the sprites are created at the end of the frame or the beginning of the next frame. However, just update the count value the next frame. In your cap file this could be done for example by adding a global variable.
Is global variable 'SomeName' equal to 1
+[do the update]
+System: Set global variable 'SomeName' to 0
On Go clicked
+System: Set global variable 'SomeName' to 1
>(the expression from trigger once goes to [do the update], the event must be deleted here)
But pay attention to the order, because if you place "Is global..." after "On Go..." it would be called in the same frame, and you would have the wrong count again