I think it makes sense to move uc_echecknet_terminal_form(), uc_echecknet_terminal_form_validate(), and uc_echecknet_terminal_form_submit() into uc_echecknet.admin.inc so they don't have to be parsed and loaded into memory on every page request. Of course this also means adding a 'file' => 'uc_echecknet.admin.inc', element to the menu items array in hook_menu().