Well more so they are speaking the same "language" really..
It's a standard... and implies equal # of photons regardless of wavelength.
"PAR" (black rectangle lines rectangle) Lumens and ONE expression (species dependent, in this case an "average"of species.. McCree curve) of PUR...(or weighted "PAR" if you prefer)
When one converts Lumen measurements to "PAR" this includes assumptions as to the losses based on the measurement..
Every light will have a different conversion factor..Oddly it is pretty similar across many light types..
Just understand it (conversion factor) is an estimate..and has been checked, for accuracy, by many..
PPF is just area-less
1 mole of photons = 6.022 x 1023 photons. 10 to the 23rd power..but load o photons
uMole 10 minus 6 of a mole.