Billing Deadlines

Key point

demurrage and detention invoices

A billing deadline is a date, not an instant. Each one is counted in calendar days from day zero, and the deadline day itself is inside the window.

Every deadline counts from the anchor: the date you choose as day zero. The three windows — issue, dispute, resolve — are yours, and none is defaulted. A blank window is left out of the call, and the result names which one is missing and says why it is null.

Lane 1 is the issue window, lane 2 the dispute window and lane 3 the resolution window. Each has its own pattern and number. The anchor, the invoice date and the request date are marked A, I and R, so the strip reads without relying on colour. The strip draws what billingTimeline returned; nothing here computes a deadline.

1. Set the dates and the windows

An invoice issued on day 30 of a 30-day issue window: on or before the deadline. The dispute window opens the same day.

Dates

Anchor date (day zero)Invoice issued on optionalRequest received on optional

Windows, in calendar days

Issue window (days)Dispute window (days)Resolution window (days)Agreed resolution date optional

2. The chain

MonTueWedThuFriSatSun

• Aanchor, day zero
• Iinvoice issued
• Rdispute request received
• 1 issue window, solid
• 2 dispute window, dashed
• 3 resolution window, dotted

These are date comparisons. What follows from a date after a deadline is for you and the terms you bill under: GMT computes dates, not liability.

3. What billingTimeline returns

 

Worth trying: the same 30-day windows, invoiced one day later — the invoice deadline does not move, but the verdict turns to after the deadline. Then a contract with 14 days to issue, 14 to dispute and 45 to resolve, and the request moved to 20 March — one day past the 14-day dispute deadline, and the request verdict turns to after the deadline while the resolution deadline stays null.

Reference: billingTimeline lays out the chain; convertUtcToPlainDate reduces an instant to the billing party’s local date before it is passed in. The rules for reading the strip are in Intermodal: Billing Deadlines.