Yesterday morning I unlocked HAM5&6 HEPIs, unaware that VAC needed back up on that chamber to disconnect turbos. This afternoon, Mitch and Ibrahim helped me re-lock those HEPIs. Because we didn't think any alignment work would be needed before unlocking again, we didn't use the normal procedure to try to preserve HEPI position, I just turned off the loops and we engaged the stops. Even so, the biggest offsets from operating position are less than 50 um/urad, most are more like 10.