For all the love of PK designs, I continue to be at a loss to explain the very odd regulated behavior (ie. the dramatic stepped decline) of the Icon series, compared to the relatively flat regulation of the earlier LED lights that were under his purview at SF. The CPF discussions at the time did not settle upon any engineering explanation (thermal regulation was considered and eliminated as a candidate), and even PK declined to go into specific details as to why their regulation was so unusual, compared to earlier SF lights.
I will certainly credit the adequate thermal limiting of SF's P60LED dropin discussed earlier in this thread; the circuitry effectively adapted to all-nitrolon G2's just as well as all-aluminum 6P's, for example. The basic handicap of that particular dropin was the heatsink patent that Gene M had on the Malkoff series of P60 dropins, from what I understand.
But the bottom line was that the Malkoff M60L or LL just /buried/ the SF P60LED for outputs and runtimes, at only a modest additional cost. Plus their considerably-superior reliability; there certainly were a number of CPF discussions about failed / burned out P60LED's. No such discussions about failed M60L's or M60LL's, IIRC.