Even the most skillful and careful writers need their documents double-checked before publication. No person or automated spell-checker is infallible. Typographical errors, misspellings, and formatting mistakes can be missed when writers check their own work.
Why not use a skilled professional to avoid embarrassing errors in your publications? I have proof-read and "sanity-checked" hundreds of documents before their publication and can ensure that your publications are accurate, are consistent in their presentation of information, and meet your own high standards.