Contract with offerred price of 100 $ , buyer seller ratio of 80:20 and ceiling price of 110$, that means seller will get 100$ definitely irrespective of cost occured. Lets consider a case

Case 1 - if cost runs to 200$ then buyer will bear 80$ and seller 20(cost to seller is 120) but since ceiling price is set as 110$, seller will not get more than 110$.So seller has to bear a loss of 10$.

Case 2 - if cost runs to 150$ then buyer will bear 40$ and seller 10$(cost to seller is 110$) i.e zero profit to seller,This is point Total assumption.

By definition : ceiling is max price that buyer will pay.

PTA : Actually it depends on contract type, however a generic are, point where seller assumes cost, or where profit is zero(it is not always true however a hint) or where buyer seller ratio does not hold any meaning

 Can PTA be higher than the Ceiling Price? 

My logic says it cannot be higher than the ceiling price. It should be less than Ceiling Price.

It is actually below Ceiling Price as shown in this picture from Wikipedia: http://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/PMP_FPIF_Contra...

However, I found a case when PTA is higher than Ceiling Price (example 1) at www.deepfriedbrainproject.com/2009/10/point-of-total-assumption-pta-facts.html

I cannot explain this to myself. Can somebody help me understand?

Ceiling Price is 100,000 while PTA is 101,666.

If I am not mistaked, PTA is the point starting from which all additional cost overruns are covered by the seller.

However, I believe that if costs reached the Ceiling Price that means that buyer will only cover Ceiling Price and all additional cost overruns will have to be covered by the seller. How come then PTA can be higher than Ceiling Price?

Can it also be smaller than Target Price, BTW? :)

In wikipedia - presented picture is technically incomplete. I have uploaded a updated pictorial presentation with proof of formula - in my blog spot -  er-sspawar.blogspot.in, it is 1st topic posted on 15 april 2012.