Once the contact information is public, it would always be available for all prospective buyers irrespective of ads posted in any category and cannot be hidden. With the activation of the paid limits package, a user can post ads beyond the defined free limit in the stipulated category. Package activation makes the contact information public so that the prospective buyers can directly contact the seller. This increases the chances of fast selling of the products.  

NotePlease note that posting an Ad in an incorrect category will consume the limit of that category, even if it has been later changed to a more appropriate correct category.