Given their primary mechanical similarities, I would imagine the rebuild periods and expense to be near identical for the KA and VLR.
The frequency of a rebuild depends heavily on how much running a “season” looks like for you as well as how competitive you need the motor to be.
Usually the order to replace things is to do a piston after x time then every second rebuild to do the bottom end. I can’t imagine a piston/top end and a hone being more than $250. Some people will do that every race, that doesn’t mean it’s necessary however for performance or reliability. It’s just what some people do because they can and it’s a great psychological advantage.
I will say, for most people, $1500 half way through a typical season does strike me as, eh, excessive let’s say and surplus to your requirements 
The truth always lies somewhere in the middle.
Lets just assume the company in question is being “overly proactive”