LDRXN_0_A is LDRXN.
LDRXN_1_A is LDRXN for variant coding (allroad)
I'm not sure about it. I disassembled r-file and didnt find any references to LDRXN_1, found only to LDRXN_0. Also if I remember correctly, LDRXN_0 sets max rl for AT also, from my experience )