At the time they called off the DSO, prices were sub $150 and...

At the time they called off the DSO, prices were sub $150 and went down to mid $80's so it wasn't only profitable at $200 but rather they were faced with a falling price, Chines curbs and given the risks was a no brainer.
The project economics in all previous studies has been around the production of a high grade, low impurity concentrate that attracts a significant premuim.
When Magnum started its activities the price was $105 and if you read everything was around concentrate production. Once the IO price went crazy they obviously looked at it and in my opinion made the correct decision to focus on value add.
Magnum's DSO plans were to take advantage of a portion of the orebody that could be easily upgraded to DSO.
This was only for limited time and it was always until the concentrate was produced and DSO would stop.

The former feasibility online showed that transport costs were about 60% of total costs for concentrate. During the pandemic they would have been even higher.
Now they intend to upgrade material onsite and then make a smaller tonnage of material and a far higher value of material.
With the focus on US steel producers and particularly the west cost, the removal of shipping costs should have a significant impact on costs.
They may export some material in some format but the local market should have a significant impact on the cost of transport in the DSO model.
I hope that makes sense.