Flood Insurance and Sea Level 1929 basis?

I had a disturbing, at least to me, conversation with a surveyor a few days ago. Flood elevations, apparently are mostly based on 1929 readings and benchmarks. In 1988, a new more accurate model became available. Several years ago, at least one governmental agency stopped using this older data.

Why am I disturbed? This new data is apparently as much as 1.08 feet off in our area. In other words, unless I misunderstood the surveyor, sea levels were on average 1.08 feet higher than the 1929 data indicated. This, to my alarmist mind, meant homes might be 1 foot lower and flood certificates might be in error or even might mean that insurance based on a certain elevation might be based on a flawed model.

See the link below to read more.
http://en.wikipedia.org/wiki/Sea_Level_Datum_of_1929

This site has a conversion calculator for your coordinates.

http://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl

I am not sure if this impacts insurance and existing homes or not, but it is interesting to me.

...follow up 4/29/08

Well, I have been busy looking for a definite answer to this. According to Fred Lindes at the Fernandina Beach Building and Zoning office, COFB goes by the 1988 data. I still have the same concerns about 1929 data and here's why. What if you have a home built in an AE11 flood zone at an elevation you thought was correct based on a certification from 1929 data? What should you do? His suggestion and mine is to get a new updated flood certification based on the corrected data to be sure you are paying an insurance premium for the correct elevation if your certification is based on 1929 data.

I will follow up again with information from the National Flood Insurance program. I left a message and have e-mailed them to see what they suggest for our area.