The DME limit may be a limit from a DME not co-located with the aid on which the holding pattern is based, eg. the DME limit could have been from CBR DME which is located at the airport, whereas CCK may not even have a DME, and is located several miles from CBR airport.
Hence a CBR DME limit of 14nm might limit the aircraft to an outbound distance of only 5 or 6 miles from Church Creek (CCK).
A leg limit of 14nm would effectively make the length of the outbound leg 14 miles, from the fix on which the hold is centred (CCK), but would exceed 14 DME from Cantberra - in this example it would extend to 19 or 20 nms from CBR.
To double check the accuracy of the length of the outbound length to confirm that it complies with the restriction, some pilots might enter CBR in the "fix" page, and then enter 14 (miles), which will show a 14 nm radius around (in this example) CBR.
Clear as mud??