I'm doing a different pp'd pattern. Bought what I thought would be an accurate amount of fabric plus a bit extra. I think I will probably have to buy more. I traveled about the same distance (to Lancaster, PA) for my fabric.
My thought process - if I need more, I can always order from the same shop I originally purchased - or elsewhere now that I have the name/number of the fabric.
I agree there is quite a bit of waste with pp'ing anything. But you can't beat the accuracy! I bought about 3/4 the fabric amount as EQ calculated I needed for my king size quilt. The young lady helping me in the quilt shop used a quilter's reference guide and looked at the backing fabric requirement to help me in deciding quantity for the top. It would never have occurred to me to do that!