I'm not sure why you insist on stipulating that PTOI will be the consumer of whatever plastics we are talking about; clearly, their business strategy is selling their processors to producers / consumers of waste plastics, not trying to buy plastic and process it themselves.
Is that another assumption underlying the simple math formula - that PTOI will only continue to try and buy waste plastic to process at their Niagara plant? Because that one can be quickly refuted.....