What can you do with 84+8 F-16 that you can't already do with 84?
PAF doesn't have Mirage 5 ROSE III? This upgrade gives an improved night-time precision strike capability to the Mirage with the addition of a new SAGEM navigation/attack avionics suite. IIRC a new PAF squadron was raised on 19 April 2007, No.27 Tactical Attack "Zarrar" Squadron, to operate the Mirage 5 ROSE III fighters and specialize in night-time surface strike missions.
PAF doesn't have JF-17? PT-04 was fitted with a fourth-generation avionics suite that incorporates sensor fusion, an electronic warfare suite, enhanced man-machine interface, Digital Electronic Engine Control (DEEC) for the RD-93 turbofan engine, FBW flight controls, day/night precision surface attack capability, and multi-mode, pulse-Doppler radar for BVR air-to-air attack capability. In April 2016, Air Marshal Muhammad Ashfaque Arain said that, "JF-17 needs a targeting pod, as the jets’ usefulness in current operations was limited due to lack of precision targeting. To fulfill this gap the Air Force was interested in buying the Thales-made Damocles, a third-generation targeting pod. Why F-16s rather than targeting pods?