OK a different question. If I want to account for the length can I do the following?

My shaft is 29 inches.
MY BH is 1 inch.

So could I say in my caluclations that my arrows are 30 inches and subtract 8 grains form my broadhead weight to make up the difference.

So instead of a 29 inch shaft and 100 grain tip could I say I have a 30 inch shaft and 92 grain tip???? Thanks