Convoy S2+ LH351D/SST20

1200lm at 3A? And 1800lm at 5A?
I guess you took this data from the Texas_Ace test.
But he tested the cri70 version. Simon has the cri90 leds.
Looking at the maukka test of the cri90 version at 3A it is <1000lm, and at 5A <1300lm.

In addition, both tested LEDs are 5000k, and 2700k will significantly lower these lumens.