SQL Syntax

This query needs incorporated in the query below:

SELECT SUM(Cost_JTD)
FROM
(
SELECT MAX(jc.JTDCOST) Cost_JTD
FROM jcost jc
INNER JOIN sccode s ON s.SCCODE = jc.SCCODE
INNER JOIN sctype t ON t.SCTYPE_ID = s.SCTYPE
WHERE jc.JOB_ID = 7398
AND t.SCTYPE_ID IN (1,7)
AND jc.DELETED = 'N'
GROUP BY jc.SCCODE
)
A;

It needs to replace the similar cross query at the bottom in BOLD. I want to return the SUM, not several rows of MAX(Cost_JTD)

SELECT
       t.SCTYPE 'Desc', t.UM 'UoM',
       FORMAT(SUM(c.POPU), 0) 'Orig Qty',
       ROUND(SUM(c.POPU) / SUM(c.POPU / c.POUEST), 0) 'Orig PR',
       FORMAT(c.POEST, 2) 'Orig HR',
       FORMAT(SUM(c.POPU / c.POUEST), 0) 'Total Hours',
       CONCAT('$', FORMAT(SUM(c.POPU / c.POUEST) * c.POEST, 0)) 'Est Cost',
       ROUND(SUM(c.POPU / c.POUEST) * c.POEST / SUM(c.POPU), 4) 'Est Unit Cost',
       FORMAT(m.Placed_JTD, 0) 'Placed_JTD',
       FORMAT(l.Hours_JTD, 0) 'Hours_JTD',
       CONCAT('$', FORMAT(jc.Cost_JTD, 0))  'Cost_JTD',
       FORMAT(m.Placed_JTD/l.Hours_JTD, 2) 'Actual PR',
       FORMAT(jc.Cost_JTD/m.Placed_JTD, 4) 'Unit Cost JTD',
       CONCAT('$', FORMAT(SUM(c.POPU / c.POUEST) * c.POEST / SUM(c.POPU) * m.Placed_JTD, 0)) 'Est Cost',
       CONCAT('$', FORMAT((SUM(c.POPU / c.POUEST) * c.POEST / SUM(c.POPU) * m.Placed_JTD) - jc.Cost_JTD, 0)) 'Variance',
       FORMAT(jc.Cost_JTD/l.Hours_JTD, 2) 'Avg HR'        
FROM ccode c
INNER JOIN job j ON c.JOB_ID = j.JOB_ID
INNER JOIN sccode s ON c.SCCODE_ID = s.SCCODE_ID
INNER JOIN sctype t ON s.SCTYPE = t.SCTYPE_ID
CROSS JOIN (
            SELECT SUM(m.PLACEMENT) Placed_JTD
            FROM materials m
            INNER JOIN `release` r ON m.RELEASE_ID = r.RELEASE_ID
            INNER JOIN ccode c ON r.CCODE_ID = c.CCODE_ID
            INNER JOIN sccode s ON s.SCCODE_ID = c.SCCODE_ID
            INNER JOIN sctype t ON s.SCTYPE = t.SCTYPE_ID
            INNER JOIN job j ON m.JOB_ID = j.JOB_ID
                  WHERE m.JOB_ID = 7398
                  AND t.SCTYPE_ID IN (1,7)
                  AND m.DATE_PLACE <= '2014-01-15'
                  AND c.TM = 'N'
                  AND m.DELETED = 'N'
           ) m
CROSS JOIN (
            SELECT SUM(l.HOURS) Hours_JTD
            FROM labor l
            INNER JOIN ccode c ON c.CCODE_ID = l.CCODE_ID
            INNER JOIN sccode s ON s.SCCODE_ID = c.SCCODE_ID
            INNER JOIN sctype t ON s.SCTYPE = t.SCTYPE_ID
            INNER JOIN job j ON j.JOB_ID = l.JOB_ID
                  WHERE l.JOB_ID = 7398
                  AND t.SCTYPE_ID IN (1,7)
                  AND l.DATE_WORK <= '2014-01-15'
                  AND c.TM = 'N'
                  AND l.DELETED = 'N'
           ) l
CROSS JOIN (
            SELECT MAX(jc.JTDCOST) Cost_JTD
            FROM jcost jc
            INNER JOIN sccode s ON s.SCCODE = jc.SCCODE
            INNER JOIN sctype t ON t.SCTYPE_ID = s.SCTYPE
                  WHERE jc.JOB_ID = 7398
                  AND t.SCTYPE_ID IN (1,7)
                  AND jc.DELETED = 'N'
           ) jc
WHERE j.JOB_ID = 7398
AND t.SCTYPE_ID IN (1,7)
GROUP BY t.SCTYPE;