the scenario!

I compare a row( selected via vlookup or a drop down menu)
I compare the returned row of data with sales figures.

i then overtype a new row with arevision- i want to then save it back to the worksheet.

How would I do this

Table amending by overwriting table?? what formula index/match
I have a requirement to look at a products sales-which I have in a table format product by week no.

I want to collate my forecast ( tabled the same)

Then while the exsitjng tables are viewed ( in a consolidation sheet-for example named result on the attached)

I want to be able to overtype the new forecast.

I can see how to present the data( using Index and Match)- but I cant figure out how to overtype the forecast and feed it back to the original forecast table.

I thought I may use the camera feature to display the actual table (using a drop downlist to expose the product I wanted) then over typoe the camera view-I can use the exisiting formaulae to express the sales and forecasts onto a graph to calculate means etc?

I have added some basic tables attachedtest sheet amended link.xlsx