So, I guess, technically I can solve this problem by keeping the first custom field with store value unchecked so that it is able to source the unit price value & then creating a second custom field which stores value and have a workflow update the second field's value with the value of first custom field in a schedule (maybe once a day) - But I think that this is not a good practice. Has anyone faced similar issue and found any better solution? If yes, can you please share how you solved it?