This question only concerns Lot 13 and not lots 1-12. As the work will be executed on the Commission's premises in Luxembourg, the service has to be available on the official working days of the European Commission in Luxembourg. As indicated in the tender specifications page 26, Section 3 "Information on the contract", 3.1.2. "Ordering processes": "Services shall be provided on the basis of Time & Means orders, which correspond to the order of a number of days performed at the Commission’s premises (i.e. intra-muros). In a Time & Means order the Commission specifies the workload (e.g. person-days) and its specific needs for requested profiles."