Resolved: Unable to use ALIASES in subquery inside SQL Select clause

SELECT 
     InvoiceId,
     InvoiceTotal,
     (SELECT 
       AVG(InvoiceTotal)
       FROM Invoices) AS InvoiceAverage,
     InvoiceTotal - (SELECT InvoiceAverage)
FROM Invoices;

SELECT InvoiceId,
       InvoiceTotal,
       AVG(InvoiceTotal) OVER () AS InvoiceAverage,
       InvoiceTotal - AVG(InvoiceTotal) OVER () AS YourAliasGoesHere
FROM dbo.Invoices;