1) Sum of each row on visits and the total number are different. 2) Results 'Unspecified' when create table for traffics from keywords.

yes the system metrics like unique visitors will de duplicate the numbers against the dimension and will show accordingly. But user created metrics like clicks on a button etc will add up and show on top. Which will basically overlap based on dimension selected. For example if you select day as dimension, then same user will be counted twice if they came on two separate days and clicked on the button while showing on the top.