I am having exact the same issue.  I have tried to keep repeating the pattern of the diagram.  Since the number of stiches in the rows can be devided by 4 (one pattern is 4 stiches and this gets repeated 14 times in row 4 for example), so should be ok, but problem is that visually it does not look correct. I think maybe that is also because of the fact that when I crochet in spiral, my stitches tend to lean to the right and are not exactly on top of each other, but I am not sure.  I am struggling with this too.