That someone must have a very special discount on buying sensors then....
The price of a new Credo 80 is about 8000 USD higher than that of an Aptus-II 12, so a 15K trade-in price is fairly reasonable I believe.
The reasoning may be a little circular here. Faced with significantly more than 15K to upgrade my Leaf 12 to a Credo 80, which is still crippled compared to the IQ180, it made more sense for me to upgrade to the phase product. For a little more than half of what the Credo upgrade would have cost, I was able to upgrade my Aptus 12 to a used IQ 180 with 2300 clicks and a full warranty. The final straw for me was that the cost for upgrading from the Aptus 10 was the same as the Aptus 12. So buy a flagship product and get screwed. Could not be happier with the IQ 180.
Henrik, I would consider this before shelling out for the Credo, as the IQ still offers more.