Wow! I've never paid much attention to feathered stars before (looked too complicated for me). I did some Googling this morning, and you're right - they do nearly always have equal numbers of points on all sides! This has absolutely blown me away!
Once I discovered this, I had to figure out the difference. Basically, if the star is based off a square centre with HST's for the points, they will have different numbers of spikies. If the centre is an octagon, they will have the same number of spikies. Thanks for helping me learn something today!