Hi All. I think people are confusing proportions - and blaming makers etc.
Chronicles - ED-209 and Cain are based (and cast off) on the actual stock motion puppet. These puppet/s could be any size depending on how larger/small they needed to build them for looking right on camera (and with the types of lens used) when the original movie/s where made. In this case they (Chronicles replicas) are the size (and proportion) the original prop was made (there are many photos floating around with the original item next to Chronicles replica).
(Hypothetically - When the actual movie was made - if they movie makers felt they only needed an ED-209 at the size of a postage stamp to do the stop motion then that is the size they would have built it - and thus Chronicles would have been the same)
Please do not take it out on the makers if you feel Cain and ED-209 are too small or too large against each other - these are the sizes they where actually made by the original prop makers. They were never designed to be in proportion sitting on a collectors shelf - 20 odd years later.
In regards to Robocop itself vs Chronicles - ED-209 and Cain in size - there are various makers of of Robocop - McFarlane, NECA, Enterbay, Hot Toys and PCS (in a few months). Again these where never designed to be in proportion to Chronicles. These 1:6 scale (or the like) are taken from the representation (size) on screen not the actual movie puppet - so yes in that regards Robocop (Hot Toys or the like) is going to be bigger than Chronicles stock motion puppet replicas.
A better proportion comparison would be Hot Toys ED-209 1:6 up against Hot Toys Robocop 1:6 - then you are comparing apples with apples.
The above comment is not to insight a Thread war - it is just to point out why there is a difference in scale.