Event structure, case structure, iteration number

Hi
I am trying one example about Event Structure from the book,  LabVIEW for Everyone: Graphical Programming Made Easy and Fun. 
The example in the book looks like this:
The number of 'work done' equals 'iteration number'.
But when I build a Vi and try this example, I got this:
iteration number is two times the 'work done'.
I have attached my Vi. Does anybody know what's wrong with my Vi
Thanks
Bing
Solved!
Go to Solution.
Attachments:
do some work.vi ‏10 KB

Both Activation and Deactivateion of the boolean causes Value Change events, but you only add 1 when it's activated. If you set the booleans mechanical action to Latch instead of Switch they should be the same.
/Y 
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    Aalenox wrote:
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