let's take a simple example, let's someone lives by himself but has 1 kid that spends 1/2 a year with him then that should be 1.5 people for the home. If the person has that 1 kid for 1/4 of the year then it is 1.25 people.

In essence what he is saying is the equation should be the sum of people * the %of days the people spend there. If someone lives there 100% of the time they count as 1 if they live there 50% then they are worth .5 and if 20% then .2