Try using the LIST feature in WO-G.  When the screen asks if it is a Kit issue, enter a "L".  Then enter the quantity of assemblies being issued and a screen comes up listing all the BOM components and their needed quantity up to but not exceeding the current on hand quantity.  If you enter a 0 as the assembly quantity, then it will calculate the quantity needed to bring all components to 100% of the work order quantity.

This weekend (3/26) update includes WO-G that shows WO Required Qty, Prior Issue, Balance needed and UOH for single component issue