For buyers contracting authority
Pick 72591000 when the contract's subject is the service level agreement: drafting the availability and response targets, the measurement regime, and the penalty mechanics that bind a service provider. A contracting authority reaches for it when it needs the governance layer around an IT service defined and documented, rather than the service delivered.
The boundary that trips authorities is that an SLA is usually a clause inside a bigger deal. Where a support or maintenance contract simply contains service levels, the primary CPV code follows the dominant deliverable: software maintenance points to 72267000, helpdesk and support to 72253000. Reserve 72591000 for cases where defining the agreement is itself the procured output, or where it is the cleanest fit for a support engagement whose whole point is the measured service standard.
The award history bears this out: Polish, Danish and Maltese authorities tag support, servicing and maintenance work here when the service-level commitment is the spine of the contract (TED 2009-2026).