SET-O confusing question

[pm107]

Section 12 C: Documents.

"For the period before you were granted leave as a Tier 2 migrant, documents showing that
you met the relevant requirements of the immigration rules"

What documents are required? I was always a Tier 2 migrant, just changed employers once.

[CR001]

Skip the question if it DOES NOT apply.

It is mostly for migrants combining Tier 1 and Tier 2 to make 5 years.

[Kal79]

Thanks Cr001 for your help. One more question, system does not allow to put same date of leaving and entering u.k. so what should we do in this case???please let me know so i can complete online application...