How to upgrade licence to SGP3.0


I have both SGP2.0 and SGP3.0 in one account (When SGP3.0 published, I purchased for a new licence instead of upgrading the original licence). And now I want to upgrade the original SGP2.0 to 3.0 version
But I cannot find where to upgrade.
When I visit the store page the price was brand new licence for $99 and a line writes login to see upgrade price.
But when I logged in, nothing happend except that line was gone.


here is what I see in the page


You already have 3 licenses for SGP3. Are you wanting a total of 6?