Hello M - I wish to share my experiences regarding Pak Punjabis.  I visited Pakistan 2 years ago along with my family.  We attended a wedding at Narowal of one of my best friends who lives here in U.S.A.  We travelled around Punjab province extensively during the week that we were there too.  Mostly I got the feeling that educated Pak Punjabis mostly spoke in Urdu and the uneducated folks spoke in Punjabi.  My friend`s family all speak Urdu to each other, only their parents speak Punjabi.  They have told me that growing up, their parents stressed that they learn Urdu over Punjabi.  They only know swear words in Punjabi.  I always kid around with them that they are not real Punjabis unless they learn the language.  I hope going forward that Pak Punjabis will stress their mother tongue more.