Qualcomm parameters

Hi experts,
Does anyone knows what is the NV 04212 parameter for in Qualcomm UEs? I was using an X55 and it was not able to register to LTE. I was told that I could play around with this parameter and it turned out that when I changed it from 28 to 19 it started detecting/registering on LTE b3 cell. Any idea about the impact of this parameter. Thanks in advance.