Change supplier after a breakpoint, keep the historic data but change new data

[Fraistan]

Hi, 

I have a spend dashboard that are being shown to the business
We are manufacturing products, therefor we have suppliers of different components (part number/SKU). 

When we change suppliers, the change is decided by a breakpoint in Serial Number.

Component: 650304
Supplier A before serial number: 340000 
Supplier B after serial number: 340000

Of course there is also a change in price when we change supplier. 

The raw data we can manipulate, these changes doesn't occur that often. 

I have 4 columns
Supplier name
Part number
Price per Unit
Breakpoint (in serial number). 

Supplier Name	Part Number	Price Per Unit	Breakpoint
Supplier A	650304	1000	340000
Supplier B	650304	950

How should I do with the raw data and what formula could i use to save the historical data but change the supplier after a certain breakpoint?