It might also come at the cost of either severely scaling back CPEC or completely abandoning it, which invariably means doing the same with Pakistan-China relations. The US is not in the business of sharing technology unless they get something much bigger out of it; politically or financially or both. Abandoning Thunder programme - or the CPEC - would be like abandoning Pakistan itself.
The US has had suspicions that Pakistan might share the tech & experience of F-16's finished product with China, and hence the stationing of the US personnel in Pakistan and F-16s not being allowed to leave the country. Giving away a production line, which provides greater insight into the F-16's technology (that too, Blk 70/72), would be unfathomable for them under this fear.
Assuming that what is being implied here - the idea of a new F-16 aka Indus Viper - it is most likely an F-16 Blk 70/72 to be produced by LM in the US based on PAF's requirements. At best, two squadrons might be purchased. It might be prudent, however, if we could secure some spare parts production and sizable supply of AMRAAMs & Sidewinders before hand. If the US stipulates that the spare parts production & subsequent usage takes place under the supervision of its personnel, so be it.