Understanding Society User Support

BHPS contained psu and strata variables in the household sample datafiles not in the xwavedat datafile so there is a psu and strata variable for each wave a-r. When running analyses using BHPS linked with Understanding Society using all available data (i.e. those who did not continue into understanding society as well as those that did) is it alright to use the psu/strata variables from the last available wave for the BHPS sample that did not take part in waves 2 or 3 of Understanding Society as their psu/strata variable data will be missing from the Understanding Society xwavedat datafile?