Nynaeve didn't think about what she was doing, she just did it. So RJ explained how the mechanics worked, but it seemed to me that she didn't work it out in the same way Rand id. Also, keep in mind that he has a Talent for Travelling - it seemed intuitive to Rand because things of that nature come so easily for him; Nynaeve doesn't even think through most of her Healing techniques - she goes off of intuition, and is just begining to not utilize herbs as before. I am not saying it's a character flaw, but it is an element of her personality and her skillset.

Plus, Rand has Lews Therin in his head and some of the experience leaks out to this life.