Entourage's Title Case Addresses feature allows imported contacts to be formatted correctly for consistency in addresses.
Fortunately, I came across Title Case Addresses (Entourage) software which effectively resolves this issue. This software works by transforming all fields to Title Case including first names, last names, titles, job titles, company and department fields, as well as street addresses, city and postal codes of both Home and Work postal addresses.
Now whenever I import my contacts, I can trust that they will be formatted correctly and ready for use. The only requirement for using Title Case Addresses (Entourage) is to have Microsoft Entourage. Overall, I am extremely satisfied with this software and would highly recommend it to anyone facing the same issue.