This is my out put of your test
tc@box:~$ mount /mnt/sdb1
tc@box:~$ mount | grep sdb1
/dev/sdb1 on /mnt/sdb1 type ext4 (rw,relatime,barrier=1,data=ordered)
tc@box:~$ sudo mount -oremount,delalloc /mnt/sdb1
tc@box:~$ mount | grep sdb1
/dev/sdb1 on /mnt/sdb1 type ext4 (rw,relatime,barrier=1,data=ordered)
tc@box:~$ sudo mount -oremount,nodelalloc /mnt/sdb1
tc@box:~$ mount | grep sdb1
/dev/sdb1 on /mnt/sdb1 type ext4 (rw,relatime,barrier=1,nodelalloc,data=ordered)