Discount fares on internal PNG flights

I keep reading on this site that Air Niugini has discounted internal fares (“wantok” fares) for people who have bought international Air Niugini flights into PNG. However when I contacted the Air Niugini “ehelpdesk” to inquire about these discount “wantok” fares (and told them I had bought international flights already), they told me that the only discount fares they have online are the same expensive “restricted economy” fares that anyone can buy online even if they have not purchased international flights. Does anyone have any idea how to obtain info about these discount wantok fares and how to buy them? Is it necessary to wait til arrival in PNG to buy them? If any of you live in PNG or are traveling there now, can you check for me what the “wantok” fare is from Madang to Port Moresby (I know that the “restricted economy” fare for that is PGK 318.10 or $123.63 including tax online). Thanks. Susan

I've been told that Air Niugini has a domestic air pass for tourists although I cannot find any information about it. Anyone heard/used this? Is it worth it?