I am using a Funnel conversion chart to look at unique visitors over a 4 week time period and what the drop off is at each stage (marked by a different page view). 

However, I get two odd things happening: 

1. When I download the data I can see it on a daily basis and aggregated up into a “total” row. Why does the “total” row not equal the sum of the daily rows?
2. When I separately pull “number of unique visitors to homepage” (the first stage in the user journey) in a different chart (a table) for the same time period, I get a different number again - not equal to either the total row or the sum of the daily rows. 

As a result, I’m confused as to how many visitors my site really has and which of these numbers to trust. 

Thank you so much in advance!