Scenario's For Cattle Gain Cost Calculation = If()

We're trying to figure out future cost of gain in cattle utilizing a table and current wt. With in the table there are two different cost stages per lot. The cost are differentiated by current size. Can do this on paper all day long but want to implement the math into a spreadsheet to streamline a bit. I have scenario detail within the attached spreadsheet.

Thanks in advance.. Happy New Year..!