Design Studio behaviour according to query read mode property

How does Design studio behave according to the Read Mode property set here in SAP : (RSRT transaction, query properties) :

It seems like Business Objects tools (Analysis, Webi, …) don’t behave in the same way according to these properties, even if they all use the BICS protocol. What is Design Studio behavior?

In fact, I’ve tested 2 queries, both with many free characteristics (because I swap dimensions in my charts thanks to scripting), but

• one with default values on CALMONTH (12 last months),
• one with a customer exit variable that I set with the exact same values (12 last months),

when analysing the behaviour in RSRT I see that choosing the H option will add a where clause to the 1^st query, “SQL” seems then identical in
both cases, and statistics are the same (see below). With A option, the 1^st query statistics are worse and the 2^nd one statistics stay the same.

So knowing if Design Studio takes this option into account is important.

At the beginning, I was expecting that Design Studio would retrieve more data cells with the default values query (all months are retrieved and some kind of local filter is applied to display only the 12 last months) than with the variable query (only the 12 last months areretrieved, no need to apply any additional filter, and if the end user wants some other months then the script has to update the variable, and waiting time would then be worse). I guess it could be true with read mode option set to A.

I know that some answers have been given on this subject, saying that even updating only default values thanks to the filter panel was implying a roundtrip to the back end, but I can only understand this statement if H option is taken into account by Design Studio…

I would like to better understand exactly what is Design Studio behaviour, and if there is any benefit to use variables to set queries filters (filter panel usage is not straightforward then), or if default values and native filter panel usage is ok as it has the exact same consequences on data volumes retrieved, back end roundtrips and query performances.

I guess that the answer depends on the capacity Design Studio has or not to take the Read Mode option into account.

Thanks in advance!