Bow weight and draw length are only part of the story. How well you release the string is also a big player in what spine you need. Some folks need stiffer arrows than the chart shows, some do better with weaker arrows and for others the charts are perfect. Traditional archery needs a lot more personal fitting than you can get by with using mechanical releases and compounds. If those arrows you're using fly good for you and hit where you point them, don't worry about it.