The proceeds of any assessment imposed pursuant to an approved district plan shall be held by the chief fiscal officer of the municipality until disbursed to the designated district management group. A business improvement district shall operate on the same fiscal year as that of the municipality. None of the proceeds collected pursuant to Sections 21-43-101 through 21-43-133 shall be used for any purposes other than those set forth in the approved district plan. Improvements provided by a district using district funds may be undertaken only when the service, events, project or activity undertaken is not for the sole benefit of any particular property owner or other private party.