We have renamed Post Grid plugin to Post Grid Combo
I'm curious if your paid version supports sorting by alphabet (last name - or other meta_key data)
I found a post on the forums but it seems that maybe this plugin is no longer supported. I can't seem to find it in your list of products now.
Welcome to our forum.
You probably didn't notice the pro feature mentioned in "Query orderby"
I hope pro version will solve your issue, please let me know if you interested.