Ryan's recent halog entry 159631 suggests that the position differences appear to have gotten worse in slug 28, the first slug after the move of the laser spot on the cathode. Also, as pointed out by Jay Benesch in a recent Elog entry 1297977, the PZT study of the adiabatic damping in the machine as analyzed by Chao also indicates a big change after the spot move. Perhaps we are seeing evidence in the Hall that correlates nicely with the PZT measurement of the adiabatic damping - a nice confirmation of the utility of that diagnostic, if true. Note that it takes us a slug to see the effect (eg 16 hours of solid data), but the PZT scan takes 15 minutes. However, I don't really understand how/why the change might be related to the spot move. Also, note that the position differences still appear (based on that one slug) to be quite tolerable.