The comparison sheet still has two cells marked “still unknown.” Someone is already saying: install for two weeks and see. The vendor mail also says “trial.” Two weeks later the whole shop is on the new flow and the old machines are in the store — that is not a limited trial. That is dragging unknowns into service.
A limited trial is one of the three allowed conclusions: keep the current system; limited trial; switch when written conditions are met. It is not a free-trial promo, and not a fourth line that means “go live and figure it out.” What must be on paper is scope, term, rollback path, and who decides to widen or stop.
Scope: write stations, shifts, functions — and what stays on the old system
“Trial” alone is not enough. Write which workstations, which shifts, which functions go to the new side; dine-in, bar, takeaway, day-end, changes, refunds — which still run on the current system.
Scene: bar only for two weeks; hot pass and floor cash stay on the old till. If peak merge and split are not in scope, the floor will temporarily push dine-in over too — once scope breaks, rollback and comparison go false.
Every extra block in scope is another face to reconcile, train and cut back. What you will not open, write clearly “out of this trial.” Do not verbally agree to “have a quick look.”
Term and rollback: lock start and end; keep the path open
Fix start and end dates in advance. At the end you must land on one of three conclusions: keep the current system; widen or move to “switch when conditions are met”; stop the trial and roll back. Do not replace a conclusion with “extend and see,” unless you change the term in writing and change scope and signals with it.
During the trial the rollback path stays open: old system, credentials, needed devices still usable; trigger signals and decision-maker named. Signals must be visible examples: cannot finish day-end that day; a must-have payment path fails; kitchen backup cannot run and tickets keep disappearing; count or money gaps you cannot explain. Write time limits too — e.g. within two hours of open, before first day-end.
Scene: in week two, “status unclear” charges pile up past open. If paper already says a deputy may stop the trial that day, you do not wait for the owner’s meeting. If it does not, shift staff can only drag.
Ask the vendor under review in writing: trial boundary, whether stations or functions are limited, how to export or keep tickets from the trial period at the end, what they do when you cut back to the old side. This shop still follows its own scope sheet and rollback drill; vendor “you can trial” is not the same as this shop having written a limited trial.
Hook it to the three conclusions: widen, stop, or return to keep
Observations in the trial go back on the same decision sheet: test task, expected, actual, status (pass / fail / still unknown). Do not open a separate “feels fine” sheet.
At the end you may only change to one of three conclusions:
Keep the current system: the trial did not prove it worth widening, or risk and load are larger — write a decision with reasons.
Still a limited trial: only if scope or term changed in writing and rollback stays open; not an open-ended extension.
Switch when written conditions are met: items that had to pass in the trial have passed; remaining opens become tickable conditions; no cutover date until those ticks are done.
Scene: two weeks end; whether a payment interrupt can tell if money left is still “still unknown,” while kitchen backup drilled pass. The conclusion may be keep, or a narrower trial with new start and end; it may not be “unknown, full-shop cut anyway.”
Who may declare widen, stop or rollback — write the post and the deputy. Staff report signals; they do not close the shop’s conclusion.