WEIGHTED AVERAGE COSTING METHOD Excluding prior-period work and costs creates some bookkeeping and computational complexity that can be avoided if certain conditions are satisfied. costs of production remain very stable from one period to the next, then it may be posi to use the weighted average method. This method does not track prior-period output costs separately from current-period output and costs. The weighted average method picks up beginning inventory costs and the accompanying equivalent output and treats them as if they belong to the current period. Prior period output and manu. facturing costs found in beginning work in process are merged with the current-period output and manufacturing costs. The merging of beginning inventory output and current-period output is accom- lished by the way in which equivalent units are calculated. Under the weighted average method, equivalent units of output are computed by adding units completed to equiva- ent units in ending work in process. The equivalent units in beginning work in process included in the computation. Thus, these units are counted as part of the current are period's equivalent units of output. The weighted average method merges prior-period costs with current-period costs by simply adding the manufacturing costs in beginning work in process to the manufac- turing costs incurred during the current period. The total cost is treated as if it were the current period's total manufacturing cost The illustration of the weighted average method is based on the same Bienestar Company data that were used to illustrate the FIFO method. Using the same data high- lights the differences between the two methods. The five steps for costing out production follow. Cornerstone 6.9 shows the first two steps for the weighted average method and Cornerstone 6.10 illustrates Steps 3 to 5