8 or 12 unit?
8 in the first batch, 4 in the second. All will be delivered by 2019.
We need several squadrons of top multi-role to counter IAF. Perhaps we will see many of this item plus the Mig-29 sqn revamped. However, my assessment is that our F-7s will be replaced with Chinese ac eventually to be our deadly counter threat.
It appears that the F-7s will serve few more years (as the F-7MBs are being overhauled at BAC) while BAF is opening a new squadron with J-10Bs (not replacements). I guess BAF has plans to replace the F-7s with J-31s in future, so they want to buy time with the life extension.