Copying orders and prices into another Excel sheet
There's likely many factors at play here, but here's my two cents:

It looks like you're copying whole cell's onto another sheet for calculation, and again to a results sheet.

What will be happening here is that when copying the values, it will be copying all the information about cells and not just the values. By adding a cell to the watch list you can see just how much information is there that in most cases you don't need (this is just a small section of the entire list):


I would suggest reviewing your copy method to copy only the information you actually need (quite possibly just .Value), this will save both memory and processing.