Need Help! Questions on Acme Lead Nuts for Joes 2006

I am starting to put together the materials for my Joes 2006 Machine and I want to use a 5 start screw on the x and y axis. I am a little confused but the Hardware List requiring 18 leadnuts? The cost of that many 5 start lead nuts might push me away from using the 5 start lead nuts. Is there another way around this?

Thanks,
Bill