Try this:
SELECT CASE WHEN $[$38.14.number] * $[$38.11.number] <15 and $[$38.1.0] = 'A00001' Then 15
ELSE $[$38.14.number] * $[$38.11.number] END
Try this:
SELECT CASE WHEN $[$38.14.number] * $[$38.11.number] <15 and $[$38.1.0] = 'A00001' Then 15
ELSE $[$38.14.number] * $[$38.11.number] END