In plain English
FAR 52.247-28, Contractor’s Invoices, is a contract clause prescribed at FAR 47.207-9(c), most recently dated Apr 1984. The complete official text is reproduced below, verbatim, from GSA's published FAR source files.
Its text contains no sentence requiring insertion into subcontracts; see the flowdown section below for what that does and does not mean.
Does it flow down to subcontracts?
No flowdown mandate found in the clause text
We scanned the full clause text and found no sentence directing the contractor to insert this clause into subcontracts. That is a statement about the text, not legal advice: a prime contractor may still flow terms down contractually, an agency supplement (DFARS, VAAR, …) may add requirements, and clauses listed below (if any) may order this clause into subcontracts from the outside.
Where it's prescribed
As prescribed in 47.207-9(c), insert the following clause in solicitations and contracts for drayage or other term con- tracts for transportation or for transportation-related services:
Prescribing reference: FAR 47.207-9(c).
The official text, verbatim
As prescribed in 47.207-9(c), insert the following clause in solicitations and contracts for drayage or other term con- tracts for transportation or for transportation-related services:
Contractor’s Invoices (Apr 1984)
The Contractor shall submit itemized invoices as instructed by the agency ordering services under this contract. The Contractor shall annotate each invoice with the contract number and other ordering office document identification.
(End of clause)