The table below provides the aggregate plan of messanger bags produced by Timbuk2. It is known that the firm uses a chase plan. The firms labor cost is $11/unit, hiring cost is $200 per unit of increase, and unit firing cost is $400 per unit of decrease in production. Given this information, what is the number in the cell with the question mark? (If needed, round your final answer to nearest whole number.

\begin{tabular}{|ccccccc|} \hline Month\# Forecast\# Net requirement\# Prod. rate\# Labor cost\# Hiring cost Firing cost \\ & & & 1,000 & & & \\ Jan & 1,800 & 1,700 & 1,700 & 18,700 & 140,000 & 0 \\ Feb & 2,000 & 2,000 & 2,000 & 22,000 & 60,000 & 0 \\ Mar & 180 & 180 & 180 & 1,980 & 0 & 728,000 \\ Apr & 100 & 100 & 100 & ? & 0 & 32,000 \\ May & 1,500 & 1,500 & 1,500 & 16,500 & 280,000 & 0 \\ \hline \end{tabular}