Comparing traffic web data

Hi I need an anlyst. web site open minded for an easy issue ( for people who worked in the e-commerce sector) I the file below there is a file excel who contains a report of the data of the web site from 13 March untill 7 may. The data extracted are: total unique visitors, other web sites unique visitors, Search Engines Unique Visitors, Typed/Bookmarked Unique Visitors and Social Networks Unique Visitors. The same is for the pages views are devided for each segments. I have to prapare some analysis which I'm able to do but I don't have knoledge about reports of web sites. And here there is an issue which I would like ti would be to sort it out. Assuming for example that the TOTAL UNIQUE VISITORS contains the search engines, other web sites, typed bookmarked and social networks, I don't understand why calculating the sum of those it doesn't corrispond of the total wirtten in the report in the TOTAL UNIQUE VISITORS. The same for the pages views. As well If I use a vertical sum for each column I don't understand why the result doesn't match with the total already written in the file at the top of the column. In the file there are any formula any problem becasue is just a report. I need to understand what's the problem. I would like if some one had experience in e-commerce or web sites analysis able to explain me for example if I can assume that TOTAL UNIQUE VISITORS contains the other segments, or not and if not of does it work to understand this report to be ready to do after my analysis. The file is attached below. Many thanks.