Group by Calculated Column, Tabular Editor

Greetings All, 

Needing some help here.  Using a SWITCH function I created my rows.  I am having difficultly creating the "Net" portion for the rows.   Anytime I try to add/subtract in the SWITCH it gives me errors.  I've spent a couple of days trying different examples I found online and have not been able to resolve my issue. 

Any help would be greatly appreciated. 

ie: "Freight in Expense" - "Freight in Income" = "Net Freight in Expense"

This is what I want it to look like:

Here is my SWITCH:

VAR _FiE = 'TableA'[AcctNbr] = "1111"
VAR _FiI = 'TableA'[AcctNbr] IN { "5555", "6666"}
VAR _DI = 'TableA'[AcctNbr] IN { "8888", "7777" }
VAR _DE = 'TableA'[AcctNbr] IN { "2222", "3333"}

RETURN
SWITCH(
TRUE(),
_FiE, "Freight Income",
_FiI, "Freight Expense",
_FiE-_FiI, "Net Freight Expense”,
_DI, "Delivery Income",
_DE, "Delivery Expense",
_DE-_DI, "Net Delivery Expense"
)

Thank you.