Autosum doesn't work the next day

Question

Hi, i've got a strange problem: Autosums in a PDF work right after creating the PDF, the next day i open it and autosum doesn't work anymore.
Step by step:
0. System: OS X 10.8.5
1. The basic form is created in ID CS6 (8.0.2), exported as interactive PDF.
2. In Acrobat 10.1.9 (and 9.5.5, exactly the same) i assign all associated fields a format for euro-currency (e.g. 123,56€)
3. Then i activate autosum on the fields for the sum and chose the fields to be summed up
4. Save as "enhanced functions for Acrobat Reader" (or whatever it reads in english, i use the german versions)
Right after this, it usually works on my system, i also tried  Acrobat Reader (11.0.06) and everything is fine. Then i send those PDFs to my client and it works only 1 out of 10 times. And the most strange thing is: a day later i tried the exact same PDFs on my system again and autosum isn't working anymore.
Questions:
- Is it possable to implement the sum function in handcrafted js in Acrobat? Maybe thats more reliable?
- As i understand it, the "one click" method in Acrobat simply creates some js from a template. Are there any security-settings influencing this created autosum-js?
- Why can't things like "format" and "autosum" not be applied in ID? Everytime i have to change something in ID, i export new PDFs and then i have to do all those steps in Acrobat again and it doesn't even work!
Thanks and regards,
Jan

Answer 1

https://www.dropbox.com/s/uiwsxoewu2mayl4/Formular%20100%20Jahre%20WW1%20-%20Mehrere%20Tr% C3%A4ger%20-%20DE%20-%20Kopie.pdf
Page 7. At the top there are four columns, the second and forth are to be summed up in the fields below the line (after "insgesamt").
Right now it works only on the second column, not on the fourth. But i did the exact same steps to enable the sum-function on both.
This PDF is NOT saved as "enhance for reader" so it must be opened in Acrobat pro.
Thanks and regards,
Jan