It could be the field calculation order is incorrect. Did you create this form and is it available online so we can test it out?
I found the something.....
When you disable "Protected Mode" Adobe Reader calculate incorrect!!
After i enabled, the calculating is correct!!!
sorry, but its german...fill the following form out.....
I really don't think this has anything to do with Protected Mode being active, but rather how you have coded your calculation scripts. For example, the line:
event.value = user_calc_fz(tempval);
event.value = "";
You have a lot of other code, such as the user_calc_13 function, where you need to change this type of thing as well.
well..at the moment it only works, when i disable/enable the protected mode. I can´t change the script, because i didnt make the form...its a public form from the Federal Ministry of Finance / Austria.