Bill,
Here is how i was able to achieve what your looking for. Try using the “code block” node, i always seem to have better results. For some reason it extracted an extra value blank so i had to remove it from the list. The best way i know to add all values of a list together is used Lunchbox tool “Mass Addition” for this you have to convert your area to a Number via String then back to number. Let me know if you find an easier workflow
Thanks,
William
