Hello Mike,
It sounds like you have a race condition going on somewhere in your Vi. This is where the local variables are not being updated appropriately. It may be because you have not initialised the local variable at the beginning of your code. Try simply inputting a constant at the beginning of the code to see if this will help solve it. In my past exaperience with this, the only thing that may prove an issue is that the value of this local variable will remain constant until the input changes again. So if you have an input that is constant and changes very few times over a long period of time then this will remain at the value it is intitialised to until the input value changes. If your input is fluctuating continuously then this may not prove a problem for your application.
Another alternative would be to use a shared single process variable in a project. You can replace all instances of the local variable with this and it should update continuously for you.
Have a go at using these and let me know how you get on.
LeeM
NIUK