Forecasting and dates, answered in full.

Start counting this week and forecast anyway. Four weekly throughput samples give a crude range that beats an invented date, and you widen the gap between p50 and p85 to reflect how thin the data is. Do not borrow another team's velocity or an industry benchmark: the point is that the numbers come from this team's own flow. Until the samples build up, lean on gate dates as the primary signal, because they are observable from day one and need no history to mean something.

Give them one date: the p85. That is what the range is for. You plan the team against the p50, you commit externally to the p85, and you keep the p50 inside the team because outside it the earlier number is heard as the date. Say the p85 is a date you expect to beat five times in six, based on the last three quarters of this team's throughput and an item count you publish alongside it. That answer survives week nine, which a confident single date does not.

The date stops being the variable and scope becomes the variable, so run the simulation backwards. Ask how many items this team finishes by the fixed date at p85, compare that with the item count in the epic, and the difference is scope you cut now rather than in the final fortnight. Take it out explicitly, restate the epic's planned currency value at the reduced scope, and have that accepted by name. A fixed date with unfixed scope is not a commitment, it is a countdown.

Any movement that puts the p85 past the committed date on the table, however small, and any gate date that moves at all. Everything else stays inside the team. That rule keeps escalation cheap and credible: the accountable person hears from you rarely, and when they do it always means a decision is needed. Escalating every wobble in the p50 trains people to ignore you, which is how the week-eleven surprise reaches teams that were technically reporting all along.