No, it's fine either way.
Here's how I got roughly 10 heads, though... When measuring the head, I didn't include the extra height added by the hair; instead, I estimated where the top of the skull would be. And I measured with the legs straight, not spread. (Both of those adjustments are customary when measuring proportions.) I was estimating when I wrote 10 heads; actually, the original figure was about 9.75 heads. But she's wearing 4" high-heels, so call it 9.5.