Manually changing  the NodePort range, apart from 30000 to 32767  is possible.  

$ oc patch network.config.openshift.io cluster --type=merge -p '{ "spec":{ "serviceNodePortRange": "29000-32768" }}'
network.config.openshift.io/cluster patched$ oc get network -o yaml cluster
apiVersion: config.openshift.io/v1
kind: Network
...
spec:
...
serviceNodePortRange: 29000-32768

The cluster should forbidden such configuration at first.
With the error message or warning message.

3. Why does the customer need this? (List the business requirements here)

The node port range can be expanded bellow "29999" without error.The OCP cluster which expanded the node port range bellow "29999" is not supported.The node port range cannot be reverted after expanding it below "29999".If the cluster is expanded the node port range bellow "29999", it must be rebuild OCP cluster to revert to supported cluster.4. List any affected packages or components.
NodePort service

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