You do have the option on the Dispatch Board to extend or shorten a Multi-Day Job. This is helpful for scenarios where actual work doesn’t quite go to plan. Both options are available from the Actions dropdown list.
If, for example, you logged hours on the last day of the job but the work wasn’t finished. You could extend the job by as many days as you need. This would create additional job instances tacked onto the last day of the job. Any remaining Budgeted Hours (B. Hrs) will be allocated when the job is extended. If you were out of B. Hrs before extending the job, there will not be any B. Hrs allocated to additional job instances.