Why the ALL row does not match the total of the individual Territory rows in Analytics?
Since the same Account can be in multiple Territories, then it is expected that adding up all the Territories may be more than the ALL row. The ALL row is supposed to represent all the Accounts. If the Territories add up to more than ALL, then it indicates that there are Accounts assigned to multiple different Territories from the report.
CRM Help Documentation: Viewing Reports in the Analytics Tab