Price Book customization for pricing model not based on discount

Price Book customization for pricing model not based on discount

Hi, 

I'm having trouble customizing the Price Book module.

#1 
First, in Setup > Customization > Layouts > Price Books, the field "Pricing Model" is not customizable.
The existing values to pick appear as "Par tranche" and "Par palier" which is in French where it should be in English.
I want "By Range" and "By Floors" and that those two values correspond to a given Pricing Details (locked and not removable from Price Book Layout).

"By Range" would mean the corresponding discount is applied only to products of quantities within the range.
Example:
        From    To              Discount (%)
        0          A               x
        A+1      B               y
        B+1      C               z
For a quantity of B+k<C, price would be (x*A+B*y+k*z)*List Price

"By Floors" would mean the corresponding discount is applied to all the products.
Example:
        From    To              Discount (%)
        0          A               x
        A+1      B               y
        B+1      C               z
For a quantity of B+k<C, price would be (B+k)*z*List Price

#2
Second, these pricing models associate a quantity to a discount.
I need to associate a quantity to a fixed price.
Example:
        From    To              Value
        0          100 000      $4 500 
How can I add this kind of model to the pick list of "Pricing model"?

#3 
Third, I guess once #2 will be solved, I'll have to add a formula to compute the good value to put when doing a quote.
Will need help for that. 

Thanks