Adding new extents to database

I need to add an extent to a database with 49755 empty allocated blocks.
The new extent will be in a volume with sufficient space.

Current db extent structure
d /vkusa01/vkusa.d1 f 450016
d /vkusa02/vkusa.d2 f 450016
d /vkusa01/vkusa.d3 f 90384
d /vkusa02/vkusa.d4 f 450016
d /vkusa02/vkusa.d5 f 469136
d /vkusa01/vkusa.d6 f 216528
d /vkusa01/vkusa.d7 f 450016
d /vkusa01/vkusa.d8 f 450016
d /vkusa02/vkusa.d9 f 38160
d /vkusa03/vkusa.d10 f 450016
d /vkusa03/vkusa.d11 f 450016
d /vkusa03/vkusa.d12 f 304912
d /vkusa03/vkusa.d13 f 450016
d /vkusa03/vkusa.d14 f 450016
d /vkusa02/vkusa.d15
b /bifiles/live/vkusa/vkusa.b1 f 250016
b /bifiles/live/vkusa/vkusa.b2

I create st file to add 2 extents
d /vkusa03/vkusa.d16 f 450016
d /vkusa02/vkusa.d17

Results after running
# prostrct add vkusa vkusa_add_0822.st

Formatting extents (blocks, path name, time):
450016 /vkusa02/vkusa.d16 00:00:08
1 /vkusa02/vkusa.d17 00:00:00

Length of /vkusa02/vkusa.d15 is 1 block(s),
which is too small to be fixed.

Minimum length is 32 K.

Does this mean that /vkusa02/vkusa.d15 is empty?

If it is? Should I remove the empty extent and create new extents below?
d /vkusa03/vkusa.d15 f 450016
d /vkusa02/vkusa.d16

Thanky you for your help.

I believe that you can't remove extents once they are created.
Why don't you go for "EnableLargeFiles" and create a variable size extent?
You created extents with a size of 450 MB which is pretty small these days. For example, I have an extent that is 20 GB in size and still growing.

You can remove empty extents.

An extent can be empty because you have never written any data to it or it can become because you have removed previous data and then truncated it.