If I had to guess I'd say the 10 since it is the computer actively computing it. It is not something like statistics that are only calculated during tick change but something must change as it occurs otherwise people could spend metal they didn't have. Just an educated guess on my part not entirely sure. I can test it on RC for you in the morning though.
Thanks. I was thinking of using those scans to check if a player's online by checking consumption (This especially works in Havoc to those using all the metal to create forces.)