Compound system Vs power strike

Hi there,
Planning the limbs shape/ length/ strength for my reverse limb crossbow project, this morning i've made several silly measurements using a toy crossbow (reverse limb configuration, with 45% angle between limbs):
I measured the differences between limbs' tops with the crossbow cooked and not-cooked
1. classical setup: the rope was secured at the both ends of the limbs without any pulley:
the limbs' variation of 40cm for a draw length of 19 cm - so, as expected, the report is about 1/1 (1 cm draw length = 1 cm of each limb movement)
2. "semi-compound" setup: two pulleys were attached to the limbs tops and the wire was one piece encircling the pulleys:
limbs' variation of 30 cm for a draw length of 30 cm - again, as expected, the report is 1/2 (1 cm draw length = 1/2 cm of each limb movement)
3. compound setup: the rope coming from a pulley was attached at the end of the opposite limb:
limbs' variation of 16 cm for a draw length of 32 cm - the report is about 1/4 (1 cm draw length = 1/4 cm of each limb movement) - I don't know why, but i was always convinced the the compound report should be 1/3 ... maybe because I was seeing just 3 wires )