Report to find time taken to deliver

Would like to see a report of time taken between receiving sales order and delivery note submission. Also, the time/delay between target delivery date and actual delivery note.

Is there any related KPI? Am I missing this report somewhere?

You can create a new script report for this if you have Admin access. This should not be much of a difficulty - jsut calculate in the unit (say days) you want the difference between the delivery date in invoice with the date in delivery note