أَكْرَمْتُ الضُّيُوفَ، خَاصَّةً كِبَارَ السِّنِّ.
I honored the guests, especially the elderly guests.
The singled-out group was already included in the general statement. Mentioning it highlights special concern: the specific after the general. It does not retract the honor accorded to the other guests.
أُعْجِبْتُ بِاجْتِهَادِهِ، لَا بِكُلِّ أَقْوَالِهِ.
I admired his diligence, not all of his statements.
Here the added qualification prevents an unwarranted inference of total endorsement. That is the logic of iḥtirās. Classify amplification by the benefit it adds, not by a mere count of extra words.