An incremental backup will backup will backup all the new and modified files since the last full or incremental backup.
Your scheme is no good since it will produce a mess. I don't know exactly when your incremental backups are done, but lets assume that they are run on Mon, Wed. and Fri and after the full backups.
Mon. - Full backup - B2T. The incr will backup files since the Mon. full B2T backup.
Tue. - Full backup B2D
Wed - Incr backup will backup files since the Tue full backup
Fri. - Full backup B2D. The incr will backup files since the Fri. full B2D backup.
Essentially, the incremental backup on Mon and Fri will backup nothing since they are done almost immediately after the the full backup.
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If the incr backups are done on Tue. and Thu.
Mon - Full backup, B2T
Tue. - Full backup B2D. The incr will backup files changed since the Tue. full backup
Thu - Incr backup will backup files since the Tue incr backup
Fri. - Full backup B2D.
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Stick to one scheme. Normally, people will do a full backup on Fri and then incremental backups on Mon - Thu. Preferably, all the backups should be to the same type of media, but you can mix media. Do NOT mix full and incremental backup at a random fashion like what you are doing at the moment.
