Replace values ​​without knowing the order?

[#1]

nesecito replace a value in a field other than I want, cualquiera.ejmp

Data:

ID       type      Cost   

Meat    MP    1000

Meat    MP   2000

Meat    MP   1000

MY      Nails  0.60

MY     BAND  0.70

My     role      0.15

Pivot Table:

Rgistro Type    Cost

Meat   MP       4000

MI       Nails     0.60

MI       BAND    0.70

MI       role        0.15

Time Role want I have no value of 0.15 assuming that is the sum, I have the same MP Cost Meat.

Pivot Table:

Rgistro   Type     Cost

Meat        MP       4000

MI            Nails      0.60

MI            role        4000

MI            BAND    0.70