When ordering a new holder provide model number of kiln and length of the element holder. See the Parts List for this information.
Assuming that the loading is even and the TC offsets are set equally, uneven temps in the kiln can be a simple programmable setting issue:
If a DaVinci is installed on a smooth floor and the lid is opened a lot, or left open for long periods of time, the weight of the lid will cause the counterbalance to want to lean forward.
Here are links to the manuals that go with these kilns.
http://www.hotkilns.com/dynakiln-instruct.pdf -is the H and C series instructions.