OVT Stands for Overture score.
http://inventory.overture.com/d/sear...ry/suggestion/
Searching "a1 super cloners" will get you an overture score showing how many times the term "a1 super cloners" was searched that month.
searching "a1supercloners.com" will get you an OVT With extension score meaning that the term "a1supercloners.com" was searched that many times a month. basically this means that users searched the website domain directly not the keywords.
there is alot of info about overture scores on here, do a quick search on dnforum and you will find all your answers