I got my Iberia Icon a few weeks ago. I called the CS and told them that I want it now, so they asked me which of the existing Iberia Sendo cards I want to cancel. In a few days I got my new shiny black Iberia Icon. I made a purchase the same day and in about a week I got my Iberia Plus status updated to Iberia Plata. Interestingly, the status is showing to be valid till April 2019! So I got almost 1,5 years of Iberia Plata.
Also Iberia Plata has the benefit of check-in at Business counters, so no downgrade here, as previously mentioned. I have a few trips planned with OneWorld airlines and the status will be very handy.
The only thing I really regret is Iberia Icon 25%/50% redemption sales... Let's hope Icon will offer equally amazing deals.