second pre lien

Generally, you are not required by statute to serve another preliminary notice assuming the content of your iniital preliminary notice was correct and it included an estimated value with a rational basis at the time. That said, may practicioners (myself included) think it is a good idea to serve an amended/supplemental preliminary notice so as to fulfull one of the primary purposes of the preliminary notice -- to protect owners, lenders, and GCs against secret and unanticipated liens. Some like to follow the "Arizona Rule" and serve an amended/supplemental notice when you hit 120% of the original estimated value.