MS2DEC Functions in after processing part

[yumikim76]

I have used MS-DIAL 4.9 for Orbitrap in untargeted metabolomics. In the MS2Dec section, the alignment differs depending on whether I check 'keep the isotopic ions w/o MS2Dec.'

1)Are the feature alignment affected by annotation?or fragment pattern ?
2)Does MS-DIAL use MS2 similarity for alignment?

I do not understand the functions of this part. Could you briefly explain these functions and recommend parameters for Orbitrap in untargeted metabolomics?