The good thing is that it is working on multisite. But need to experiment more as just started.
For the time being am mentioning two findings/issues/doubts:
1) For multisite option if we want to mention search all blogs so that whenever a new blog is created it searches in all automatically instead of dragging each blog separately, what can we do?
2) When I am typing any particular product it is displaying all the products .I have selected as exact match but its displaying all.Where I am missing?