"Unbundled basis" means breaking down or separating something into its individual components or services, rather than offering them as a package or bundle. Full definition
I have a base PS4 and unbundled base Xbox One. (n4g.com)
The information and resources on practicePRO's Limited Scope Representation page are intended to help you understand some of the risks inherent in providing limited scope legal services, and how you can reduce your exposure to a claim when working for a client on an unbundled basis. (slaw.ca)
Be careful with communications when opposing counsel is acting on an unbundled basis: The commentary under 3.2 - 1A.1 provides that: «a lawyer who is providing legal services under a limited scope retainer should consider how communications from opposing counsel in a matter should be managed.» (slaw.ca)