Falling sand entities get broken when piston heads push them

I have found a sand and Gravel duplication glitch in Minecraft pocket edition 1.0.6 It utilises sand falling onto a piston I found this by trying to make a falling sand garage door for my horses I used this double piston extender here: (https://www.youtube.com/watch?v=DTQGnMP3BX8) screenshots (look at my hotbar) bellow of how I have done it I only had 5 pieces of sand when I started making my garage door now I can fill it and have 7 extra this only gives you 1 at a time though.