Work back from dispatch through the reviews that must finish first

A deadline for sending an approved pack is not the time at which staff can begin preparing it. The team needs to know which activities can happen together, which must wait and whether the remaining work still fits the commitment.

This fictional example concerns a Lebanon-connected supplier preparing a customer pack. All durations are owner-approved planning allowances for the exercise, not measured service performance or promised delivery times. The case demonstrates the dependency decision; a real schedule needs its own evidence and available reviewers.

State what dispatch depends on

The approved source pack must be ready before either review begins. A commercial reviewer checks the offer, while a language reviewer checks the customer explanation. Those two reviews can run in parallel because neither requires the other's unfinished result. Final assembly requires both approvals and uses the approved material without changing its meaning.

The planning allowances are:

The customer has agreed a dispatch deadline of 18:00 UTC on 3 November 2026. That dated instant displays as 20:00 in Asia/Beirut under the time-zone data used for this exercise. The local label helps participants recognise the deadline; it does not change the dependency calculation.

IANA's Time Zone Database maintains changing time-zone rules. A project should use maintained zone data for dated displays rather than treating one offset as a permanent rule for every date.

Calculate the latest common start

The two reviews do not add to 75 minutes when the agreed arrangement allows them to run together. Their combined elapsed preparation path is the longer review, 45 minutes. Assembly then adds 15 minutes. The planned path is therefore max(45, 30) + 15 = 60 minutes.

Working back from 18:00 gives a latest common review start of 17:00, assuming the source is ready and both reviewers can actually begin. Starting at 18:00 mistakes the deadline for the start. Starting at 16:30 by summing all three activities assumes a different, sequential arrangement.

Neither calculation establishes reviewer availability. If the commercial reviewer cannot start until later, that is a new constraint. Nor does the allowance establish a guaranteed review duration. A finding can require a substantive source correction and another decision.

Follow the ordinary ready case

For pack P-61, the approved source becomes ready at 16:50. Both reviewers begin then. The language review finishes at 17:20 and the commercial review at 17:35. Both approvals are recorded against the source pack used in the exercise.

Assembly begins at 17:35 and finishes at 17:50. The pack is prepared ten minutes before the agreed deadline. The early language result does not permit assembly at 17:20, because the commercial approval is still outstanding at that point.

The coordinator records the actual completion evidence and dispatch decision. The schedule does not manufacture an approval merely because its allotted time has elapsed.

Resolve the request that starts too late

Pack P-62 is still untouched at 17:15, with its source only now ready. Even if both reviews begin immediately and meet their planning allowances, commercial review ends at 18:00 and assembly ends at 18:15. The existing 18:00 dispatch commitment no longer fits that plan.

The coordinator does not change the customer deadline in the record and pretend it was always later. She presents the remaining work and obtains an explicit agreement to dispatch by 18:30 UTC. The record retains the original 18:00 commitment, the agreed replacement and the person who confirmed the change. P-62 then proceeds under that revised arrangement.

If the customer had not agreed, the task would remain an unresolved commitment requiring the responsible person's decision. Sending unreviewed material or silently assuming consent would not be a valid scheduling correction.

Recalculate when actual progress differs

In P-62, the language approval is ready at 17:45, but the commercial reviewer needs until 18:10. Assembly cannot start at the planned 18:00 while that approval is absent. With the remaining 15-minute allowance, the revised projected completion is 18:25.

The coordinator checks that this still fits the explicitly agreed 18:30 deadline, records the changed progress and begins assembly only after both approvals exist. The fictional pack is prepared at 18:25. Its five-minute margin is a result of this fixture, not a general buffer recommendation.

If the reviewer instead reports an unresolved source issue at 18:10, the coordinator cannot simply add 15 minutes and call the result feasible. The missing approval has no confirmed finish time. The customer commitment needs another explicit review.

Keep the independent controls visible

P-61 retains its ordinary 17:50 result; replanning P-62 does not move every pack to the later deadline. The customer-facing commitment changes only where an agreement was recorded. Neither local display conversion nor opening the work queue changes an approval or dispatch event.

The accepted operating view shows source readiness, each review's actual condition, the earliest assembly point and the current agreed deadline. That lets the next colleague understand why a pack is waiting instead of seeing only an unexplained “late” badge.

For a team-tool project, bring one real dependency chain and identify which activities genuinely run in parallel. Name the decision-maker who can discuss an infeasible commitment. A scheduling feature is useful when it makes that decision visible while there is still something responsible to do about it.