I got a slightly different impression.
I believe the discrepency is that the Rule of 86 is based on volume (gallons), where sugar content (Brix) is measured in weight (pounds). Meaning, the Brix level is the ratio of the weight of the sugar relative to the weight of the syrup, and it's not based on the how many gallons of sugar.
If everyone used volume, then the 33:1 would be correct. Or, if everyone used weight, then the 33:1 would be correct as well. The narly part is that folks are using different measurement sticks (kind of like metric versus English units).
As I found out recently, syrup is heavier than water. Per a different thread on these forums, pure water is about 8.3 pounds per gallon, where 66% syrup is around 11 pounds per gallon - the heavier weight due to sugar. If sugar and water weighed the same, then syrup would weigh the same as water.
Sugar is heavier than water (I don't have an exact number). So, if you increase the sugar weight by 33:1, you need to decrease the water by more than that to compensate for water being lighter.
That's my impression; anyone know for sure?
Rookie in 2009
30-40 Taps, 2x4 Homemade Evap, Kids to Help