i think deadlifting on volume day is fucking stupid
so you could try moving it to intensity day
you could also try doing speed deadlifts on intensity day (while keeping your DL on volume day)
if all else fails, start going for triples, then doubles, then singles, then try to set PRs in triples or 5s again and repeat until you have to do some really crazy programming
you might also need more than 7 days between efforts... try 10 or 14
i'm typing this up while i sit here in nothing but a pair of crusty, smelly boxers, so take my advice with a grain of salt
i also seem to have a different perspective than most everyone else on this forum (with regards to every subject)