Single emitter in a one-hole reflector, sure. But when reflowing 4 WFs onto a single huge pcb, each one will wiggle and pull to what feels comfortable, then set in place when the molten solder freezes.

Now you gotta drop the big honkin’ reflector over all 4. Centering rings or not, it’s lucky if they fit in the holes without constant stress pushing one/more LEDs laterally.

Now, if there were a way to precisely place the LEDs on the pcb and hold them “centered” throughout the entire reflow process, that’d work. Otherwise, they’ll still wiggle and self-center on the pads as they see fit.

Exaggerate the error. Make the “bolt circle” of the LEDs even 1mm bigger. Now none of the LEDs would fit in the reflector’s holes, not without cracking one/more LEDs as they’re shoved sideways off the pads, or just corner-crushed by the reflector as it’s shoved down onto them.