If you sort the field directly alphabetically i.e. without the val function your sort will come out as follows.
01, 02, 1, 2, 3, 4, 6
but if you add something like 10 then you will get
01, 02, 1, 10, 2, 3, 4, 6
if you are looking for something like
01, 1, 02, 2, 3, 4, 6
You will need to...