It is against ECS policy to create direct links ("hyperlinks") to content outside the document currently being viewed. As the reference is in the Installation Guide and refers to the Administration & Configuration Guide, inserting direct links from one to the other would be against this policy. Direct links are not permitted because they become invalid if the documentation is relocated. Providing the title of the applicable content is considered the better approach since titles are less likely to change.

I think that if this is as part of one documentation pack (documentation suite), there is no risk in moving as there could be relative links and moving only part of the documentation doesn't make sense to me (always whole documentation of the product would move).

But if this is a policy, then OK.