See Setting a Discount on Customer Groups for instructions on how the discount matrix works.
It is possible to import a discount matrix into Infusion. This is for Sell minus a percentage only.
CSV to import
To do this you will need a CSV with three columns
There should be no header on the CSV.
Go to Admin / Manage Import Routine, create a new routine, with the Data Type Discount Matrix, the example uses this as the import title as well. Nothing further needs to be added in here.
Import the discount matrix
Do an Infusion Backup
From Admin / Import Data, select the import routine (The import title from above)
Navigate to the Source file and select import, after confirming the import, a further prompt will display to allow you to confirm the order of the import columns.
Select OK to continue.
The confirm the discount have appeared by opening Customer / Reports / Discount Matrix By Customer Group - Summary