Round wall fit increment/interval

[Benson Shaw]

The wall fit to objects dialog includes an interval parameter for round walls. Data value seems be numeric rather than unit? So what is meaning of the interval? Vwx HELP only identifies this as the increment. Neither term is explained or illustrated, nor is there indication of effect of higher or lower values vs 0. 
 

Is this the number of points made with even division of the round wall length? Or a length of the segment between fit vertices? Or?

 

My tests with adjusting the interval number when fitting a round wall to stepped geometry above either fail or fail worse depending on value in the interval field. 
Solution is to revert to manually adding wall peaks? 
 

-B