A manufacturer has the following information on its major products:

Regular$-$time production capacity

Overtime production costs

Inventory costs

Backlog costs

$=2600$ units$/$period

$=\frac{12}{?}$ unit

$=\frac{2}{?}$ unit$/$period

Beginning inventory

$=5$ unit$/$ period

$=400$ units

Demand $($in units$)$ for periods $1,2,3,4$ is $4000,3200,2000$ and $2800$ respectively. Develop a level output plan that yields zero inventory at the end of period $4.$ What costs result from this plan?