The "Contribute now" button only shows when translation is less then 100%. Fine
But if the translations is 100% it should show a similar button for "improve translation" so users will bet a link for their language team and can be involved.

See this page:
Translations for CTransifex - https://compojoom.com/downloads/languages-cool-geil?view=project&id=8

if all languages was 100% users will never find a link to their language team or to the Transifex project... as they should!

(Btw... already asked to transifex a new role for "proofreaders" that would be excellent for those on 100% but don't want to have more editors!
Transifex | Request - New role: proofreaders without editing rights - http://support.transifex.com/customer/portal/questions/935918-request-new-role-proofreaders-without-editing-rights )