Random Start Frame in Replicator....

OK, trying to get a video wall playing lots of different video frames with all different content, etc etc that can be moved around nicely

Im trying to do this using replicator so they can start as a jumble and pull themselves together with as little keyframes as possible but im having trouble with the random start frame option. Basically, its not so random as i'd like it to be. While it is a different frame for each cell, the variance of the frame is only within a few seconds of each other. I have a 2min clip filled with short segments but it only draws from that first segment, no matter the random seed.

Is this just a limitation of the replicator? should i manually create my own wall and animate the holding layer?

thanks in advance...