I asked many times what the difference between full backup and level 0 incremental backup is.Whether or not they are the same and ...
Incremental level 0 backup which is the base for subsequent incremental backup copies all blocks containing data same as full backup. (Same functionality)
The only difference between these two backups is that a full backup never considered as base backup in incremental strategy.
Therefore, if you select incremental strategy as part of your backup strategy, you need at least one level 0 incremental backup.