When I hooked up a dispenser to a comparator that was receiving signal from a 4-tick repeater and a monostable, depending on how long the wire was between the comparator and the dispenser, the dispenser would give out different amounts of pulses.

In the first picture, the dispenser gave out 1 pulse
In the second picture, the dispenser gave out 2 pulses

The only difference made was lengthening the redstone wire between the comp. and the disp.

Notes to the pictures:
The piston is a sticky piston
The repeater is at 4 ticks delay
The comparator is set to subtraction mode