Hi!
The reason the values doesn't match is quite simple. Here's an example to make it easier to understand:
Suppose you're a user and just visited the retail site X on April 1st and you went to these specific pages:
homepage > jeans > t-shirt
When you create a report in Adobe here's what you're going to see:
Total number of users: 1
Total number of visits (session): 1
If you do a breakdown of page type by visits you're going to see the following:
homepage: 1
jeans: 1
t-shirt: 1
If you sum the values you're going to have 3 sessions, which is incorrect, because we just had one visit. What happens is that Adobe will always try to attribute visits and visitors to the page type or content type so you know which are the sections of your site that has most visits. Adobe is clever and when it aggregates the data it will do deduplication removing all the duplicated metrics.
That's the reason that the values don't match. If you want more information you can visit this section:
https://helpx.adobe.com/analytics/kb/sum-line-items-different-from-total.html
Hope that I could help