Consider the following set of processes, assumed to have arrived at time $0$. Consider the CPU scheduling algorithms Shortest Job First (SJF) and Round Robin (RR). For RR, assume that the processes are scheduled in the order$P_1, P_2, P_3, P_4$.
$\begin{array}{|l|l|l|l|l|} \hline \text{Processes} & P_1 & P_2 & P_3 & P_4 \\ \hline \text{Burst time (in ms)} &8 & 7 & 2 & 4 \\ \hline \end{array}$
If the time quantum for RR is $4$ ms, then the absolute value of the difference between the average turnaround times (in ms) of SJF and RR (round off to $2$ decimal places is_______