Here you select the general Storage Overhead mark-up in percent that will apply to the pre-calculation. The standard value for this mark-up is entered under the Calculations heading that you will find under the Manufacturing tab in the Settings procedure.
For purchased parts you can also register SO Mark-up Exceptions, for example for a purchased part that is included in the calculation but which is particularly expensive and should therefore have a lower SO mark-up. To be able to use SO Exceptions the setting Use SO/SC mark-up exceptions in the system? must be configured in the same location as above in the Settings procedure. If there are SO Exceptions saved for the part in question, then that mark-up is applied as the standard SO mark-up for that part in the calculation. You register SO Mark-up exceptions in the procedure called SO/SC Mark-up Exceptions in the Global Settings module.