Yes, Off course it will not cost PTCL when it is being accessed within Pakistan...

But it may use somewhat while resolving name to IP...

When a user within Pakistan try to access that website request is first sent to the DNS Server, which the user has specified in his PC (OpenDNS or that specified by PTCL), Then that DNS Server will check it's cache, If the IP is already resolved it will send that IP to user otherwise it will resolve it (Do you know how resolution does occur?) & send that IP to user then that user will establish a direct connection with that IP to access data...

If Site is within Pakistan, it will be easily accessible (fast access)... & it will not consume B/W of PTCL...

ok

If You're using PTCL Broadband, Have you used http://entertainment.ptcl.net/ ... It is hosted within the PTCL's own network... You can compare it's speed with others... It's always fast than others... because it's record is just added in Local DNS Server of PTCL ..When you will try to open it request is sent to DNS Server of PTCL ... It will resolve it to their Web Server...
AND you can check that this site will not be accessible if you're using some other DNS than PTCL's own...