For buyers contracting authority
Choose 72212422 when the contract is to develop an integrated suite of business modules, not a single-purpose application. The deciding question is breadth: if the build covers several connected functions delivered as one system, the suite code fits; if it targets one named function, a more specific sibling is the better tag.
The siblings are where authorities slip. Investment management (72212411), tax preparation (72212412), facilities management (72212421) and accounting (72212440) each scope a single domain. Reach for 72212422 only when no single sibling captures the work because the deliverable spans them or sits across business transactions generally.
Watch the goods-versus-services line too. This code is for developing software; buying a ready-made software package off the shelf belongs in the 48000000 supplies family. Where a single contract bundles bespoke suite development with some licensing, keep it here as long as the development is the main purpose, and set the primary CPV code by the dominant deliverable.