Redistribution of external routes has a default cost (seed metric) of 20. If using the default type 2 OSPF calculations, this seed metric is maintained throughout the network and can lead to sub-optimal routing in larger environments. To mitigate that risk, you may redistribute using metric-type 1 (Type 1 external routes) which add the link cost to the seed metric as traffic is forwarded through the environment.
In the following example, note the seed metric is altered from the default 20 cost:
Stuck-in-Active: Journal of an IT-Network Administrator 