Change of Primary UOM

Hi All,

We have a senario as below:

Current Version: EBS 11.5.10

Recently joined work here, found that most of the items' Primary UOM is defined as EACH. They are having difficulties in issuing materials in retail and also the finance and procurement is facing problems each time because of not getting the exact stock in hand. Example: Drums of 205 liters are defined as each, now I cannot have the UOM conversion done properly to issue in litres as it had to be defined in liters as primary UOM, we aren't getting proper costs and in hand details for each job done either (some work orders are with full drum cost and some