For this, we have created new flow fields in the Job Task table:
The flow field definition is quite special.
Sum("Job Planning Line"."Quantity (Base)"
WHERE (Job No. = FIELD(Job No.),
Job Task No. = FIELD(Job Task No.),
Job Task No. = FIELD(FILTER(Totaling)),
Contract Line = CONST(Yes),
Planning Date = FIELD(Planning Date Filter)))
The result is visible in the Job Task page (1002).