"(1) In assessing whether to admit the testimony of a witness as an expert, an Immigration Judge should consider whether it is sufficiently relevant and reliable for the expert to offer an informed opinion, and if it is admitted, the Immigration Judge should then consider how much weight the testimony should receive.

(2) In considering how much weight to give an expert’s testimony, the Immigration Judge should assess how probative and persuasive the testimony is regarding key issues in dispute for which the testimony is being offered."