Prefab Instances all have separate Scales?

Hey all,

(sorry if this is long, but it's a weird problem)

I have a prefab (let's call it GrassBlock), which is a modular piece for creating levels. In my game, a lot of these are assembled together to make levels. I put together a bunch of these blocks to form a play area, and everything seemed to work. After I upgraded form Unity 3.1 to 3.4, I noticed that the scale of each instance of the GrassBlock prefab has a slight deviation from the standard (i.e., 1.00000001, 1.0003,1.00000002 instead of 1). I tried applying a new scale to to the prefab, but nothing happened. I also tried reverting each to the default value, but that have no effect as well. I care about this because Unity is rendering each block on a separate draw call (due to the scale), and due to the sheer amount, the framerate suffers tremendously.

My question is: How can I get all of these instances to be a standard size?

Thanks in advance :)