Thanks to **dbltoe **and to **gjh42 **for answer me; but the suggestions is not a solution for me, let me rephrase my question:
The store will sell items with price based on the items dimensions, but the store’s admin does not have a price difference per attribute value just have a matrix price like the above example (actually is bigger than the example) and if you see the increments in the matrix is not the same on any way.
On the store side, the customer will have 2 dropdown to select width and length based on store admin already entered price, the customer don't need to see the matrix (as Product Attribute Grid do).
The point is how the store admin will enter the information to match the matrix price instead of define increments per attributes values?
Thanks in advance
jarm