If the clearcoat blocks UV this isn't true, or isn't dramatically true. I had to polish yearly until I clearcoated mine with a $20 can of UPOL clear from amazon. After a few years they very very slightly had a tint starting to move towards yellow, but it was negligable and beat yearly polishing for me. I've also read that the outdoor helmans polyurethane makes an excellent UV-blocking clear. IIRC it was to be diluted 50/50.