They lowered the NB price by $4 and doubled production cost from PEA1 to the BFS.
This is pretty easy to figure out. Just find the NPV of the Sc and subtract from the BFS NPV. I did assume equal production every year and the same pricing throughout. 103 Tonnes per year at $3675/kg with $1127/kg production gives $262,444,000 per year of net Sc revenue. Assume this starts in three years and continues for 32. We know the additional capex for the Sc is very low. I thought I remembered $30MM reported. This gives the Sc an NPV of nearly $2.8B pre tax, given the overall NPV of $2.3 this means the Nb is negative. This is exactly why the NFS itself said the project would not meet investment criteria on Nb alone.