I have a scenario to brainstorm. A finished product comes with standard parts but customer can asks for extras and upgrade to change the parts, for eg. a standard chair upgraded with different base, different handle, different colour etc. The chair sku always remains same but the additional parts on it is either made inhouse or sent to the factory supplier. Once received from factory there can be some additional work on the finished product such as spraying, drying, packing etc. SO cannot be fulfilled until this all is completed. We cannot use assembly as the exact same combination 'custom' finished product will never be the same for another order. How to handle this without using Assembly & Work Order? Also,