Backup mehod - for intervals and possible restore points

[Rob Martin]

Currently I have a nightly full backup that happens at 2am and then I take incremental backups every 2 hours after that.

Backup directory:
/backups/development/mysql/mys01ld/20150506

Sub directories:
drwxr-xr-x+ 4 mysql mysql 7 May 6 04:02 0400
drwxr-xr-x+ 4 mysql mysql 7 May 6 06:02 0600
drwxr-xr-x+ 4 mysql mysql 7 May 6 08:01 0800
drwxr-xr-x+ 2 mysql mysql 2 May 6 10:00 1000
drwxr-xr-x+ 4 mysql mysql 7 May 6 10:38 full
drwxr-xr-x+ 4 mysql mysql 5 May 6 12:00 1200
drwxr-xr-x+ 4 mysql mysql 5 May 6 14:00 1400
drwxr-xr-x+ 4 mysql mysql 5 May 6 16:00 1600
drwxr-xr-x+ 4 mysql mysql 5 May 6 18:00 1800
drwxr-xr-x+ 4 mysql mysql 5 May 6 20:00 2000
drwxr-xr-x+ 4 mysql mysql 5 May 6 22:00 2200

Here is the methods I use for my backup:

if [ "$CURRTIME" -ge 200 -a "$CURRTIME" -lt 300 ]
then
mkdir -p ${BACKUPDIR}/${DATE}/full
mysqlbackup --defaults-file=/usr/my.cnf -u $USERNAME -p$PASSWORD --backup-dir=$BACKUPDIR/$DATE/full backup ( ## line 1 ## )
mysqlbackup --defaults-file=/usr/my.cnf -u $USERNAME -p$PASSWORD --backup-dir=$BACKUPDIR/$DATE/full apply-log ( ## line 2 ## )
else
mkdir -p ${BACKUPDIR}/${DATE}/${CURRTIME}
mysqlbackup --defaults-file=/usr/my.cnf -u $USERNAME -p$PASSWORD --incremental --incremental-backup-dir=$BACKUPDIR/$DATE/$CURRTIME --incremental-base=dir:$BACKUPDIR/$DATE/full backup ( ## line 3 ## )
mysqlbackup --defaults-file=/usr/my.cnf -u $USERNAME -p$PASSWORD --backup-dir=$BACKUPDIR/$DATE/full --incremental-backup-dir=$BACKUPDIR/$DATE/$CURRTIME apply-incremental-backup ( ## line 4 ## )
fi

So my question is - when I run the full backup, lines 1 and 2 are executed and the /backups/development/mysql/mys01ld/20150506/full directory is updated
and can be used for restore back to the 2am time when the full backup was taken. However, when I run the incrementals every two hours after that, lines 3
and 4. Does the step in line 4 ("apply-incremental-backup") take the updates taken in line 3 from the time specific directory and apply those changes
captured to the full backup directory? If so, does that invalidate my ability to do a restore back to backup-0 when the initial backup was taken?

What I want to do is have a way to where I have a 2 hour roll back window every night in case needed - and possibly I can change that time
interval to every 10 minutes or as needed based upon the need of the business?