Section 8. The commonwealth shall provide financial assistance to the authority through periodic draws by the authority from the Massachusetts Bay Transportation Authority State and Local Contribution Fund in accordance with section 35T of chapter 10. Receipts credited to said fund shall consist of (i) the base revenue amount or the dedicated sales tax revenue amount as said amounts are defined by said section 35T, and (ii) all assessments received pursuant to section 9. The receipts credited to said fund shall, except as provided in subsection (d) of section 12, section 13, or section 18, meet the full financial obligation of the commonwealth to the authority.