Russians/Soviets used a doctrine wherein, why you have missiles like R-27 which have extended reach vs R77 but come in an IR and also a SARH variant, offering multiple seeker options. You will also see, in Russian combat load-outs, generally, they carry both variants of the R-27, this is something that stems from the Soviet studies where they found that launching salvo's of two missile groups, of varying seeker types to further complicate the target defensive tactics, would increase the likelihood of a kill (logically), therefore, they decided that they needed multiple seeker variants of the R27 to achieve exactly that, this has been passed down today to the Russians, who employ the same tactic (though, it probably has as much to do with the large stocks of both missile types too). THOUGH, i can probably hazard a solid guess that the PAF isnt adopting soviet doctrines, rather, AWC just thought instead of totally redesigning a missile from scratch to fit an IR seeker, it was just easier to redesign the FAAZ to fit it instead. Though remember, i dont expect these missiles to be much more than a learning exercise. When the israeli's attempted to design their own missile, the Phython-1 its performance was piss poor, resulting in zero kills, however, they took what they have learnt and they have created arguably one of the most capable family of missiles there is. Though, i fear, we are too late to the party to be able to learn from operational experience, but, i guess late is better than never.