After Installer completes configuration of LB in Public and Private Host Zones for API and APi-Int servers respectively, the LB addresses returned from this step should be used to update the AWSPlatformStatus field before starting MCO.

https://github.com/openshift/api/pull/1397 contains the updates to the AWSPlatformStatus field of the PlatforStatus struct within the Infrastructure CR. 

https://github.com/openshift/installer/blob/master/data/data/aws/cluster/vpc/outputs.tf#L47-L61 contain the LB DNS names for the internal and external LBs configured by TF.

openshift/installer code needs to be updated to use the LB DNS names from the TF output, resolve them to their respective IP address and update the LBIPAddress and RecordType field for APIServerDNSConfig (external LB) and   InternalAPIServerDNSConfig (internal LB). The record types for all of the entries is "A" at this time.