Phase loss changes visible signal by a coherent fraction, not by relabeling shots. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Four fifths coherence keeps forty visible counts
With 64 coherent shots out of 80, the coherent fraction is 4/5. The ideal visible count 50 scales to 40.
50⋅54=40
Three fifths coherence gives the capstone signal
The capstone row has 48 coherent and 32 dephased shots. That ratio turns 50 ideal visible counts into 30.
50⋅53=30
Two fifths coherence leaves twenty visible counts
If coherent shots fall to 32 out of 80, the same ideal signal produces only 20 visible counts.