Well the way it is it seems to pull all replies to a thread.
People report that it did not work in 6.3 but it did in 6.2
I have a 6.2 dosearch.php but see no reason or difference where it would break it.
I have tried a few things. However for the most part I was just happy to update the mod to be able to break apart main threads from replies when searching.
I am continually searching for the difference in 6.2 versus 6.3,6.4 that causes this to break but then I never ran this to 6.2 to confirm it worked correct there.