A higher signal pushes occupancy above one half because the signal grows relative to the same half-signal constant. With high signal 18 and constant 6, the denominator is 18 + 6 = 24 and the occupancy is 18/24 = 3/4 exactly for the stated toy binding model; real chemotaxis has receptor noise, ligand diffusion, calibration limits, cell-to-cell variation, saturation, and measurement uncertainty.
A larger signal raises occupancy without changing the receptor constant. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Higher signal changes the denominator too
The high signal is 18 with the same half-signal constant 6.