This article seems to confuse RTO and RPO in several parts. You would not adjust your RPO for the time it takes boxing, unboxing or shipping backup media. This would be factored into your RTO. The RPO specifically refers to your recovery POINT. This can be seen as a checkpoint to which one can revert the system in the event of a system failure.

The RPO should be calculated as the maximum frequency between backups. You would also not adjust the RPO for a potential failed backup. The term objective indicates that this is a goal. Whether we meet, exceed or fall short of this goal it should remain static. To schedule backups every 24 hours is to set your goal or objective of data loss at no more than 24 hours.