They have to set it to Merge Pets themselves. Personally, I use four out of the five tabs. First tab is with merged pets, damage done in percentage. Second is without merged pets, damage done in percentage. Third is DPS with merged pets, and fourth is damage done in numbers without merged pets.
When we report Swstats in the raid, I show the top 10, and it's fairly accurate. It rarely deviates from other's reports by more than 0.5 %. So I can personally vouch for it's accuracy and usability. I am going to try recount though, since I hear it's even better when it comes to breaking down the raid/group into segments you can truly analyze. As someone said, a mini WWS report.