Understanding Society User Support

Dear Support-Team,

I am trying to match the household income (e.g. fihhmngrs_dv) of parents to the children in the US and BHPS. However, when finished, I find that the household income of fathers and mothers is identical to childrens' household income. This would imply that all children live in their parents' households, which is probably not the case.
My approach was the following:
1) merge individual level data and household data using hidp -> save data
2) merge respondent and parental data using mnspid as pidp (for mothers, likewise for fathers) -> merge household data for mothers/fathers -> rename interesting variables as "m_" and "f_" -> save
3) merge the data from step 1 and step 2

This works well for adding individual responses from parents to their children. However, it does not work in the case of household data. Thus, I was wondering, is "hidp" the identifier for the original household of the respondent when he/she entered the panel? If so, how can I assess changes in households over time, so that respondents who leave their parents' household get assigned a different household income than their parents?

Thanks you very much for your help!
Sebastian