Conclusions
With 200 (per experiment) @ Ecm=198 LEP 200 can discover (or exclude) a Higgs boson close to the kinematical wall (discover a 104.5 GeV Higgs boson at the 5s level or exclude a 106.7 GeV Higgs boson at the 95% CL). (all estimations are on the average for the combination of all four experiments)
The combination of low energy data (Ecm 189) with higher energy data improves the sensitivity for a SUSY Higgs with a mass below 100 GeV.
A careful consideration should be given before exchanging 100 @ 198 GeV CM energy with 50 @ 200 Gev. Neither the SM Higgs search nor the SUSY Higgs search gains from this exchange. From the Higgs search point of view it is recommended to collect high luminosity at the maximal energy consistent with an efficient machine working point. Additional increase of up to 2 GeV in the CM energy at the price of a factor ɮ in luminosity degrades the sensitivity of the experiments to discover the Higgs boson.