Disputable Additional Work Invoice?

Questioner

Good morning, More than six months after completion in 2019, we received a supplementary invoice for additional work. This only covered labor hours. Is this contestable? Kind regards, Jan Bellinga

Questioner

In principle, yes, unless otherwise agreed. The additional work must be reasonable and not exorbitantly disproportionate. I recommend rejecting the additional work in writing. If you cannot reach an agreement and a legal dispute arises, please contact me immediately for consultation.

Questioner

Additional work must be announced in a timely manner and you must have agreed to it. If a target price was provided, the contractor may exceed the actual cost estimate by 10%. How have you agreed to pay for labor hours or the target price including labor? All of this is important.