The Secretary of the Interior is hereby authorized, in his discretion, and under such rules and regulations as he may prescribe, to collect reasonable fees to cover the cost of any and all work performed for Indian tribes or for individual Indians, to be paid by vendees, lessees, or assignees, or deducted from the proceeds of sale, leases, or other sources of revenue: , That the amounts so collected shall be covered into the Treasury as miscellaneous receipts, except when the expenses of the work are paid from Indian tribal funds, in which event they shall be credited to such funds.Provided