What is the ruling when witnesses testify to differing amounts, causes, or descriptions?

Primary text

If the causes and descriptions differ, the testimony is not considered complete evidence. For example, if one witness testifies to a thousand from a loan and another to five hundred from a sale price, or if one testifies to one thousand white dirhams and another to five hundred black ones, or if one testifies to one thousand dinars and another to five hundred dirhams, the claimant may swear an oath with either witness and claim the amount testified to by that witness, without the amounts merging.