Is the pledgee's testimony regarding the amount for which permission to pledge was given admissible?

Primary text

The testimony of the pledgee is accepted if he testifies regarding permission granted for the pledging, because this testimony does not accrue a benefit or avert a harm to him. If the pledgee claims permission was given to pledge for ten units, and the owner claims it was only for five units, the owner's statement is accepted because he is denying the increase.