Section 8(5)(ii) in The Bihar Irrigation and Flood Protection, (Betterment Contribution) Rules, 1961
(ii)In apportioning betterment contribution between an under-raiyat paying for the land held by him rent in kind and a kayimi raiyat the same ratio shall be adopted as is adopted in dividing the produce, i.e., the under-raiyat shall be made to pay 13/ 20th of the contribution and the kayimi raiyat 7/20th of it.