Well, bulbs with different brands, even with the same watt rating and K rating can put out different PAR/PUR values. Example, a UVL AquaSun that is stated as 10,000K will put out a LOT more PAR/PUR than a TRU 10,000K bulb, despite being both T5HO bulbs and using same amount of watts.
However, I doubt that your new bulbs puts out a lot less PAR than the old one to the point of "less pearling".
There's been talk of new bulbs needing a "break-in" period before they start performing best, but it's one of those things that may or may not be just another myth being thrown around.
In other words, I'm not sure what caused you're plants to do less pearling
IME this is the first sign of nutrient levels being really low and eventually leads to algae, depending on which nutrient is deficient....but you're on EI so this isn't the case for you.
BTW, EI instructs dosing GH booster after the weekly 50% water change to "reset" nutrient levels. Maybe after your next scheduled water change, dosing, your pearling might go back to where it used to....