I think there is a bug with recording calls for Accounts/contacts.

When scheduling calls from within an account, the schedule call dialog only displays a single "Related to" field, while when scheduling a task for the same account, two separate "Related to" and "contact" fields are provided.
As a result, a task can be correctly set to regard a chosen contact within the chosen account, while a call can specify either an account or a contact.
As a result, it is possible that the related to/contact record for the call get corrupted and the call is effectively "lost" from the account's view.
Steps to reproduce error:
-create one account SomeCompany with two accounts (EmployeeA and EmployeeB)
-schedule call for account SomeCompany without selecting any account.
(Seen in the activity tab, this call now has SomeCompany as "related to" an no account associate: correct).
-Now edit the task, select "related to", chose "contact" and select EmployeeA.

Now in "activities" tab the call has:
related to: EmployeeA (Should be SomeCompany!)
contact: EmpolyeeA

As a result, the call disappears from the calls list displayed within the Account of SomeCompany!
It will only be visible when displaying EmployeeA's record, but it has been lost from the account's history!
When scehduling tasks, separate fields for "related to" and "contact" are provided, and mishap doesn't happen.