Whose statement is accepted when partners disagree on the agreed-upon share for the worker in a sharecropping (Musāqāh) contract?

Primary text

The statement of the capital owner (Rabb al-Māl) is accepted. This is the position stated by Ibn Hamid. The evidence is that the capital owner is denying an increase claimed by the worker, and the principle is that the statement of the denier is accepted. This is supported by the prophetic tradition: 'The evidence is upon the claimant, and the oath is upon the one against whom the claim is made.' If one party possesses clear evidence (bayyinah), judgment is based upon it. If both parties have evidence, a difference of opinion exists regarding which evidence takes precedence, based on established principles concerning the evidence of the one entering versus the one leaving.