The quote was fine until the third revision

Where event margin goes

A quote is agreed. The client then asks for a different arrangement, an extra hour, a change of colour scheme that means reprinting. Each request is small and refusing feels disproportionate, so it is absorbed.

By delivery the job has moved substantially from what was priced, and the invoice matches the original quote because raising the changes now would sour an event that is already emotional. This is the single largest cause of loss in event work and it is entirely a documentation failure.

Price the change when it is asked for

At the moment a client asks for something extra, they are asking for a favour and expect it might cost. A message saying what it adds, sent the same day, is almost always accepted.

The same amount raised at final invoice is a dispute, because the client has by then absorbed the change into their idea of what they were buying.

Your suppliers do this to you

Event businesses subcontract heavily, and the same dynamic runs in the other direction. A supplier delivers to a changed brief and bills for the change afterwards.

Tracking committed supplier cost against the job as commitments are made, rather than when invoices arrive, is what prevents a job looking profitable right up to the week the bills land.

The half hour that pays for itself

Compare quoted against actual for every job, within a week, while people remember why things changed.

Most event businesses have never done this and are genuinely surprised by which kinds of work lose money. It is frequently the prestigious jobs, where more was absorbed to protect the relationship.