The PI certification reads as follows:
"The services for which reimbursement is requested have been satisfactorily rendered and the costs thereof are proper and due in accordance with the terms of the agreement. If this payment is for an advance, it is in accordance with the terms of the agreement and necessary to further project objectives."
The PI should only certify the above statement when they have verified that the work was satisfactorily completed in support of the scope of work and the costs are appropriate. In an audit, sponsors will look to verify that work was performed satisfactorily, not just that expenses are appropriate. Approving an invoice for payment only covers the appropriateness of expenses noted on the invoice. Therefore, the certification statement which covers the programmatic work must be provided by the PI.