Requisition UOM vs Default Stocking UOM

Here is our scenario. Inventory item 1234 has 3 UOM's. EA (standard UOM), PK (5 EA) and CS (70 EA). PK is set as the default req and stocking UOM. We have two inventory units that stock in PK and CS. A majority of requesters have a ship to with a distribution network pointed to the inventory unit that stocks the item in PK. However there will be times when they need a bulk order so they change their ship to so that it will be filled by the second inventory unit, which stocks the item in CS (We set up a fixed picking location to stock in CS). Our issue is that when they do this they also have to change the UOM. Since EA is the standard UOM and has to be marked as ordering, shipping and stocking UOM, it shows as an available UOM in ePro and requesters will sometimes select the EA UOM instead of CS. When the requisition is sourced to inventory it shows a shortage because we do not stock in EA. Has anyone experienced a similar issue or know if it is possible to have PeopleSoft convert the EA to CS when fulfilling the order?

Thanks,

Nick