Not all VSL is crystal. Their 'Luxval' line was a comparatively inexpensive range of moulded glass which was not made from crystal (though some patterns were later made in lead crystal). I haven't seen this vase in any Luxval catalogue, however, so would take the attribution with a large pinch of salt.
The vase is really lovely. I am a big fan of pressed glass and the mould work on this is very impressive. Sadly, though, I don't think it's going to be possible to get a firm attribution until either a marked example turns up or it's identified in a catalogue. While there's a fair possibility it is Czech, it could also have been made elsewhere. France, Belgium, Poland and the former Yugoslavia all spring to mind...
Have you tried contacting Siegmar Geiselberger of pressglas-korrespondenz.de? He is very knowledgeable and helpful. By making the images available to other pressed glass collectors some more information might turn up.