I'm not a lighting or electrical engineer or an aquatic plant keeping expert by any means, but I'm quite sure none of that is correct. I think we have established (or found "data") over the years that supports the plant beneficial output from LEDs will fade over time, but it takes much longer than that of fluorescent tubes....... PUR/PAR doesn't matter, it fades across the whole spectrum. You also can't use a sweeping statement to state Leds are more economical to buy or use. That is why I always recommend folks check the specifications of the Leds and compare it.
An LED is a semiconductor that emits light as opposed to a gas filled tube with arc filaments, both of which we know degrade quickly.
We can discuss this by PM to avoid further taking away from the OP's thread if you like.