I wouldn't say it is total non-story.
Was there anything like +45C at NCL or reduced TODA on that day?
Viking operates MD80 (MD83, I think). If Capt was looking to offload 70 pax this is almost 7 tons incl baggage. I can imagine unxpected temperature or wind varition would call 7 tonns off from a 747, but not from MD83. For MD83 7 tons is as much as 2 hours flying... There is something more behind this story. Just wrong aircraft for the route/load or...?