gblilbear,
Please see my post just above for issues that can arise with Sellathon counters.
You ask if you need to copy and paste Sellation into your saved templates and listings code. For new listings, if you do not have the Sellathon counter being added to your listings, you will have no counts. You can control that from your Account Preferences where the 'Append Sellathon Counters to my listing must be selected to 'yes' and you have a choice of selecting a visible or invisible counter. If you have a lot of saved listings that you relist over and over and the Sellathon counter is not in them, I think you will need to add it manually, but I would recommend contacting Auctiva Support on that question.
You ask about searching eBay with Sellathon. Sellathon Counters record hits made to your eBay listings, and Premium subscribers will see an additional "Hit Stats" column on their Active Listings page. The displayed stats let you track your sales, trends and other vital information about your listings on eBay. The Hit Stats are shown in 3 different graphs—Hourly hits, Daily hits and Daily Repeat Hits.
The functionality you mention--searching all of eBay for a keyword and telling you the best time or phrases to post for that keyword beyond what Sellathon can provide at the current time.
Hope this helps.