Bp process questions

I'm still in the BP hiring process.. so far I've passed drug,pft, SI.. medical wants me to do a follow up in something but that's no to worry... My question is I'm applying for a mortgage in these couple of months for the first time. When the time comes for the background investigation, do I tell my investigator that I applied for a mortgage even though on my e quip I said no. Or should I wait till I passed all the process?