In KeyLAB there are two ways in which to order the samples. The first is called Custom ordering which will order by top depth. The second is called Standard ordering which will order by location id and then depth. The images below show both the types of ordering.
Custom ordering
Standard ordering
To be able to change between Standard and Custom ordering there is a check box within the options. The image below shows the location of the check box. It's in the options on the locations tab.