You are making several logical fallacies.
First, in 1948, the quotas were 2% for Karachi and 15% for those with no domicile. As people got domiciled, they would not qualify for the 15%, so it was there in the beginning only to account for how many muhajjirs were already part of the bureacracy and resettling. In the long run, as the migration ended, this too would end.
As we have all been told, the quotas were placed on Karachi at 2% because they saw that most muhajjirs were migrating there and wanted to limit their future proportion in the bureaucracy.
Secondly, even if we assume that muhajjir quota was supposed to be 17%, (no domicile and Karachi), the proportion of muhajjirs has never been less than 20% at any time prior to the 60s-70s. Here is a reference that has numbers to this effect.
Unf, I am not able to find the numbers from before 1948. That would end this discussion. Again would love to be proven wrong. But I have read in numerous places that Bengalis and Muhajjirs were dominating nascent bureacracy- Muslim league.
In any case, as the paper above highlights, the proportion of muhajjirs in the bureaucracy was sharply curtailed eventually. But the proportion of Punjabis was always raised. Initially at expense of Bengalis primarily. Then at expense of Sindhis. The quotas were only there to limit muhajjirs.
Okay so you admit it. What are we arguing about then. That Punjabis played a major role. Yes they did. So did every group.