Thats a fair point Aamer, but you need to consider the demographics as well.
Multan has a huge population and is the main city of South Punjab. The next comparable city would be Hyderabad on this side. Of course, am not saying that ppl from Sindh will come and live here but certainly its located in a very potent and un-tapped market.
Secondly, while there will always be more flipping and short term investors in lahore, Multan will have the strength of long-term retaining/end-user buyers.
So even if the prices don't spike like in lahore, they will remain sustainable in my view.
With regards to supply, DHA will be doing it phase wise so it won't develop and release 100,000 plots in a go but probably 20 - 30,000 plots in first phase. And that number will easily be consumed by such a large population.
And by the time it gets to next phase, people would have the benchmark of first phase to remain interested in future phases.