In the event the balance in the account under N.H. Rev. Stat. § 237:24, N.H. Rev. Stat. § 237:40 or N.H. Rev. Stat. § 237:9 is insufficient at any time to meet the operating expenses, maintenance costs and debt service of the eastern New Hampshire turnpike, the central New Hampshire turnpike or the New Hampshire turnpike system, as the case may be, the treasurer shall transfer the amount necessary to meet the deficiency from the excess income in either or both of the other accounts. In determining which account or accounts to make the transfer from, the treasurer shall be guided by the respective needs of the accounts.