RRN in SQL and Full table scan...

Back in May there was a thread where Birgitta mentioned that "Sometime in
release 6.1? / 7.1?. the table scan for RRN was changed to an values list
access, i.e. the list containing RRNs is searched first and with the result
an access to the record performed.
​"​

A test with WHERE RRN(A) = 750000

Showed the "VALUES LIST" in Visual Explain.

However, today I tried
WHERE RRN(A) between 750000 and 750010

And I see a full table scan in VE.

This however, shows a values list..
WHERE RRN(A) IN (750000, 750001, 750002, 750003, 750004, 750005,
750006, 750007, 750008, 750009, 750010)


I'm running 7.1 TR 9.

Charles