I found this:
(B) For purposes of this chapter, service is complete upon receipt by the party being served except as provided in division (H) of section 1701.07 of the Revised Code and except, for the purposes of sections 1311.05 and 1311.261 of the Revised Code, if service of a notice of furnishing is made by certified mail, service is complete on the date of the mailing. If the service is attempted upon an owner, part owner, or lessee, or designee, at the address contained in the notice of commencement required by section 1311.04 of the Revised Code, and if the notice, affidavit, or other document is returned unclaimed or refused, service is complete when first attempted.
I'd still go see a legal person though... (edited)