Does Nitori Ultracool and supercool sheets downgrade after 4-5 wash cycles?

So as summer starts to ramp down (hopefully), Im faced with a dilemma about keeping all the ultra and super cool sheets I have for another year for next summer or just throw them away.

Just wanted to gauge if it was a truly hot summer or if Im being too picky but I felt both ultra and super cool sheets from Nitori really lost their effectiveness after a few wash cycles over the summer, but is that the same for anyone else using them?

Also side question I feel the super cool is actually cooler than ultra cool but wanted to check if thats same for others too.