My client had multiple top-level-domains. Each one represented an insurance program within a specific vertical. For all the sites at these alternate domains, there was a 30/70 mix of duplicate vs. original content. Some of the alternate domains ranked very well for their target keyphrase groups, where others were absent in results pages. We advised the client to merge multiple domains into their existing main domain, for usability and SEO reasons.

We recently ran the merger. Here was our process:

1. On the main domain, transfer the content such that it matches 1-for-1 content on the various alternate domains
2. Setup Google Webmaster Tools on the main domain
3. Push the new content on the main domain live and submit a corresponding sitemap to Google
4. Establish 301 redirects on the alternate domains, such that each alternate domain URL points to its respective page on the main domain

We did this 12 days ago, and pages (previously on the alternate domains) that had ranked well on Google have now plummeted or are entirely non-existent.

Did we do the right thing by merging multiple top-level domains into a single domain? Is this initial dip in rankings normal? How soon should we expect to see it return to its normal rankings?