Hi Tamas,
If the visual plan is not showing too much difference, probably you forgot to "Execute" again after visual plan, see on this Lars blog how to do it.
http://scn.sap.com/community/hana-in-memory/blog/2012/12/20/show-me-the-timelines-baby
Don't know why we need this step (because we always need to execute it again), but it how it works today.
Regards, Fernando Da Rós