Hi..
The difference between connections and sessions is to do with connection pooling :-
Imagine you wanted a dispatcher that could have 15 connections but only 10 doing any work. the remaining 5 would be idle (the pool). You have 10 physical network connections serving 15 clients.
The mount of time an idle connection will wait in the pool is specified using the ticks option of the mts_dispatcher parameter.
Not sure about second question.
Once you have eliminated all of the impossible,
whatever remains however improbable,
must be true.