Let me clarify this matter for most of you. I did a lot of homework on this, and my PCC has been accepted by CIC.
What matters is that you have your period in Pakistan covered from the age of 18. If you have lived in Karachi, and gone to Lahore for studies, or for work, but your permanent address was still Karachi, a PCC from Karachi suffices.
If you have moved to Lahore or any other part of the country permanently, and do NOT have an address back home eg. in Karachi anymore, then you need a PCC from Lahore as well.
Basically, temporary addresses aren’t a concern. The only concern is where our permanent residence is and whether you have covered each and everyday from the age of 18 till when you were in Pakistan.
Also, IMPORTANT NOTE. If you are residing abroad, come to visit Pakistan, say for 2 weeks, those 2 weeks NEED to be included in the PCC for Pakistan. Everyday you spent in Pakistan according to your stamps and file need to be covered.
Hope this helps.
I am not an active member on this forum so might not be able to get back in case you replied to this.
Wish you all the very best.