I own 7 Arturia FX plugins, yet I see my discount is only 100 dollars.  
On one page I see $299 for FX4 and another $199.  Both seem a bit high to me, considering what I own.
V-Collection pricing is about as disappointing for me as I own 4 of the synths outright and still only get a 100 dollar discount. 
I also see in other forums people mentioning their confusion on Arturia discount pricing -- one person even said, depending on webpage loaded, they see three different prices 89 69 and 49 for the same FX4 update!  (of course they went with 49)
I think Arturia needs a defined and visible discount structure across the board.  I really don't understand how the discount amounts are calculated.