We only restored PIT of HEPI2 (H1:HPI-HAM2_IPS_RY_SETPOINT_NOW) yesterday, but there was a change in ROLL (RX) on the order of 10 urad that was not restored, which might affect the input pointing.
Also, there was a jump in ROLL in HEPI3, again on the order of 10 urad, which would affect POP and ALS beam position on ISCT1 as well as POP sled in HAM3.
These DOFs were brought back to pre-maintenance levels.
I don't know/remember why, but it seems that a new set of angle setpoints is made for HEPI such that the system starts new with free-hanging position after each restart. Seems like this free hanging position changes over time.
Since any change in HEPI angle (RX, RY and RZ) on HAM2 and HAM3 would affect many things related to the alignment, most notably pointing references like IM4 transmission QPD and POP sled, it's a good idea to keep the set points unchanged over multiple restarts.
I've done a survey a of all the SEI Guardians with regard to the position dofs that are restored (maintained everytime.)
HAM_ISIs maintain every dof but the HAM_HEPIs only maintain the RZ dof. I'd say this is backwards given the range and more importantly hysteresis of HEPI.
While at it, for the BSCs: their HEPIs all maintain the RZ dof, the ETMs maintain their pitch and the ITMY maintains pitch roll and X dof to deal with ACB install and Initial Alignment. The BSC ISIs maintain NO dof.
It certainly makes sense to me that at least the HAM2 & HAM3 RX & RY dofs are also restored along with the RZ. Don't know why we wouldn't do this with HAMs 4, 5 & 6 too. The X Y & Z dofs are probably okay to let wander but commissioners can comment.