Upon certification to the Surgeon General by the State agency, based upon inspection by it, that work has been performed upon a project, or purchases have been made, in accordance with the approved plans and specifications, and that payment of an installment is due to the applicant, such installment shall be paid to the State, from the applicable allotment of such State, except that (1) if the State is not authorized by law to make payments to the applicant, or if the State so requests, the payment shall be made directly to the applicant, (2) if the Surgeon General, after investigation or otherwise, has reason to believe that any act (or failure to act) has occurred requiring action pursuant to section 291g of this title, payment may, after he has given the State agency notice of opportunity for hearing pursuant to such section, be withheld, in whole or in part, pending corrective action or action based on such hearing, and (3) the total of payments under this subsection with respect to such project may not exceed an amount equal to the Federal share of the cost of construction of such project.