The change lead time should be entered by Change Coordinator/Change Manager.The lead time is used to compute Earliest Start Date and it uses business hours and holidays configured for change manager's support group.
Sachin, please could you expand on exactly where this is configurable within 7.6.04 as I can't locate it from your guide.
The field is not on the Best Practice View.
If you need to use this feature, you can use it through "Template" especially for standard changes.
i think Lead Time should be configured by the Change Admin by evaluating the Type, Priority and the time it takes to implement that Change Request.... as this is a configurable factor by the Change Config(mostly the one who administrates the Change Template) it has been kept only in the Change Templates and not been exposed in the BPV as the best practise as the User might not have an idea about Lead Time for the type of Change which he is submitting....
its a design time attribute not the run time.