I have a form that I want to be able to manually change the answer to the calculation. The objective is to accept a calculated value unless the user enters a different value in the calculated field. The calculated value will usually be the value desired, but not always.
I have attached the form for help: https://dl.dropboxusercontent.com/u/11052710/Adobe%20Acrobat/Overriding%20LVEF.pdf
Not having verified with the linked form, but the symptom of being "one step behind" usually means that the Calculation Order is not correct. Essentially, there is a field whose calculation depends on the result of another field, but that field's calculations are one after the one of the first field.
Hope this can help.
This topic answers the same question : http://abracadabrapdf.net/forum/index.php/topic,3009.0.html
You can download the PDF sample given in the 4th answer here : http://abracadabrapdf.net/forum/index.php?action=dlattach;topic=3009.0;attach=2506