No worries :-)
i think my primary question is that if tab2 does not have a histogram, then why cannot tab1's range/frequency weights and range density serve as a basis for evaluating tab2
The total density IS the combined average of tab1's range/frequency weights and range density. If it estimated 700 it would making the assumption tab2.col1 is either 1 or 3, it has no idea what tab2 contains. The example I am using here is about a query with that single join condition only, no other entry in the predicate that is looking for a specific value.