I too am OB in Mesa! I've just had the gunite done, now waiting on my sub to build water feature and Ramada. I don't know what a pre-grade is. I'd think it might be where your excavator comes out to see what he has to do, before the pool is laid out in order for them to dig. I didn't do a pre-grade. I did inform my excavator sub that I had a 2' high berm of dirt all along my back wall that stuck out about 8'. Most of that would need to be dug out first and then the pool could be dug out. The excavation crew was surprised there was no layout when they showed up and I was like um aren't you guys supposed to do that? One quick call to the owner and it was all straightened out. The crew removed the extra dirt in prep for layout the next day. Took 3 days to dig (the one Saturday we actually got rain in Arizona caused a delay).