Eu tive um erro de ortografia e um problema de formatação. Ao formatar os dados finais em vez de formatar dentro da instrução SELECT incorporada, os dados da minha tabela estavam corretos.
CÓDIGO bem sucedido:
$sql = "SELECT x.company, x.stagestatus, x.shippeddate, FORMAT(SUM(x.totprice), 2) as totalprice, FORMAT(SUM(x.sgtotquantity), 2) as sgtotqty, FORMAT(SUM(x.sgtotalsqft), 2) as sgtotsqft, FORMAT(SUM(x.avgsqftrev), 2) as avgsqftrevenue, FORMAT(SUM(x.avgunitrev), 2) as avgunitrevenue FROM (SELECT t1.company, t1.stagestatus, t1.shippeddate, t1.id, TRIM(LEADING '$' FROM t1.totalprice) AS totprice, t2.invoiceid, SUM(t2.quantity) AS sgtotquantity, SUM(t2.width * t2.height * t2.quantity ) /144 AS sgtotalsqft, (TRIM(LEADING '$' FROM t1.totalprice)/(SUM(t2.width * t2.height * t2.quantity ) /144)) as avgsqftrev, (TRIM(LEADING '$' FROM t1.totalprice) / SUM(t2.quantity)) AS avgunitrev
FROM invoices AS t1 INNER JOIN lineitems AS t2 ON t1.id = t2.invoiceid
WHERE (t2.invoiceid = t1.id)
GROUP BY t1.id) x
WHERE x.stagestatus='Complete'
GROUP BY x.company ASC";
Obrigada!!!