How do I account for HHWT when looking at data about number of households in a state from sample w/ all states?

I have a similar question related to household count. When I download data for a MSA, here St. Louis #41180, using “ownership” as the only other selected field I get a household count of about 2.7 million… that is I added all the HHWT field entries for some 25 thousand records. But when I used the SDA online tool, filtering only for the MSA and pernum(1) I get a household count of 1.2 million. What am I doing wrong?