Changing the supplier cost price

I started a comment on Facebook last night and it seems many people have the same question. Why can we not over-ride the supplier cost price on copied products or add a supplier base price on our own custom products.

By being able to do this we can control our profit and loss reports making deco invaluable.

Right now the only solution is to use markup % but when a price is lower than the supplier price you cannot mark down %

We need to put in a cost price (from the supplier) then a price (to charge affiliate stores) 

Please add this feature as it seems like a very simple fix and ask.