You should upgrade now to v1.3.9h as that old version is out dated, insecure etc. etc.

It would also make upgrading to the next version easier ...

Spider comes in and runs through your site for a few hours and you get lots more hits ...

20 Spiders come in and run through your site for a few hours and you get lots more hits ...

Spiders can run on your site for a long time and multiple times ...

Note: Zen Cart v1.3.9h does not count spiders in the counter ...