So, I have completed Round IV of JS Model 13 doily, It seems to lay out quite well right now.
I was having slight difficulty in reading the stitch count for Round V because the numbers are rather small in some parts. I had an idea to look at JS other patterns from his book because I noticed that he liked to repeat some of his motifs in different doily/mat designs. True enough, the first six rounds of this doily is very like Doily IV on page 56 in his book Tatting Theory and Patterns.
I was also aware, from the discussion thread in Craftree, that there may be errors or misprints of the chart for Round V, so I was very cautious as I began to tat this, more so with my plan to reduce the number of free picots in some of the rings. But, I think I have figured it out. A marked difference are as pointed out by the red arrows in the photo below.
I made a slight change in the shape of the rings joined to Round IV.
My stand here is, any change done consistently throughout becomes a design variation. In this case, the change is too minimal to alter the big picture and that is how I will continue for this round.