Dear applicant, honestly speaking it totally depends on your confidence, how confident you are to upgrade yourself for MBBS courses. If you have got BAMS in the first round, if the college is well established then it's better to opt for that but yes if you are confident that in the upcoming round you have more possibility to get a MBBS seat in any Government or renowned private institution you can do that. But make sure the cut off complies with your confidence,

Good luck!!