fix mighty draw knack

knacks.tex

@@ -97,7 +97,8 @@ The character also gains a number of \gls{mp} equal to the number of Knacks they
 
 \subsubsection{Mighty Draw}
 
-You can draw back a hunting bow in a single \gls{round}, paying only 8 Initiative for the action, minus one per Knack you have. For example, someone with 4 Knacks would pay only 4 Initiative for the attack.
+You can draw back a hunting bow in a single \gls{round}, paying only 8 Initiative for the action, minus half the number of Knacks you have (rounded up, minimum of 2).
+For example, someone with 4 Knacks would pay only 4 Initiative for the attack.
 
 \subsubsection{Perfect Sneak Attack}