diff --git a/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh b/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh
index abf2e6d023f9b..e94bff408f874 100755
--- a/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh
+++ b/ci-operator/step-registry/ipi/conf/aws/ipi-conf-aws-commands.sh
@@ -42,7 +42,22 @@ fi
 # Generate working availability zones from the region
 mapfile -t AVAILABILITY_ZONES < <(aws --region "${REGION}" ec2 describe-availability-zones | jq -r '.AvailabilityZones[] | select(.State == "available") | .ZoneName' | sort -u)
 # Generate availability zones with OpenShift Installer required instance types
-mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort -u)
+
+if [[ "${COMPUTE_NODE_TYPE}" == "${BOOTSTRAP_NODE_TYPE}" && "${COMPUTE_NODE_TYPE}" == "${master_type}" ]]; then ## all regions are the same 
+  mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort | uniq -c | grep ' 1 ' | awk '{print $2}')
+elif [[ "${master_type}" == null && "${COMPUTE_NODE_TYPE}" == null  ]]; then ## two null regions
+  mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort | uniq -c | grep ' 1 ' | awk '{print $2}')
+elif [[ "${master_type}" == null || "${COMPUTE_NODE_TYPE}" == null ]]; then ## one null region
+  if [[ "${BOOTSTRAP_NODE_TYPE}" == "${COMPUTE_NODE_TYPE}" || "${BOOTSTRAP_NODE_TYPE}" == "${master_type}" || "${master_type}" == "${COMPUTE_NODE_TYPE}" ]]; then ## "one null region and duplicates"
+    mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort | uniq -c | grep ' 1 ' | awk '{print $2}')
+  else ## "one null region and no duplicates"
+    mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort | uniq -c | grep ' 2 ' | awk '{print $2}')
+  fi 
+elif [[ "${BOOTSTRAP_NODE_TYPE}" == "${COMPUTE_NODE_TYPE}" || "${BOOTSTRAP_NODE_TYPE}" == "${master_type}" || "${master_type}" == "${COMPUTE_NODE_TYPE}" ]]; then ## duplicates regions with no null region
+  mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort | uniq -c | grep ' 2 ' | awk '{print $2}')
+elif [[ "${BOOTSTRAP_NODE_TYPE}" != "${COMPUTE_NODE_TYPE}" && "${COMPUTE_NODE_TYPE}" != "${master_type}" ]]; then   # three different regions
+  mapfile -t INSTANCE_ZONES < <(aws --region "${REGION}" ec2 describe-instance-type-offerings --location-type availability-zone --filters Name=instance-type,Values="${BOOTSTRAP_NODE_TYPE}","${master_type}","${COMPUTE_NODE_TYPE}" | jq -r '.InstanceTypeOfferings[].Location' | sort | uniq -c | grep ' 3 ' | awk '{print $2}')
+fi
 # Generate availability zones based on these 2 criterias
 mapfile -t ZONES < <(echo "${AVAILABILITY_ZONES[@]}" "${INSTANCE_ZONES[@]}" | sed 's/ /\n/g' | sort -R | uniq -d)
 # Calculate the maximum number of availability zones from the region