D. Assessments for funds to meet the requirements of the association with respect to an impaired insurer shall not be made until necessary to implement the purposes of this chapter. Classification of assessments under subsection 2 and computation of assessments under this paragraph shall be made with a reasonable degree of accuracy, recognizing that exact determinations may not always be possible.

3-A.__Determination of assessments.__Assessments must be determined as follows:

A.__The amount of any Class A assessment, as described in subsection 2-A, for each account must be determined by the board of directors and may be authorized and called on a pro rata or non-pro rata basis.__The amount of any Class B assessment, as described in subsection 2-A, must be allocated for assessment purposes among the accounts pursuant to an allocation formula that may be based on the premiums or reserves of the impaired or insolvent insurer or any other standard determined by the board in its sole discretion as being fair and reasonable under the circumstances. This paragraph may not be a factor in the determination as to whether the protection provided by laws for residents of this State by the domiciliary jurisdiction of a foreign or alien insurer is or is not substantially similar to the protection provided by this chapter for residents of other states.

B.__Class A assessments, as described in subsection 2-A, against member insurers for each account must be in the proportion that the premiums received on business in this State by each assessed member insurer on policies or contracts covered by each account__for the calendar year for which information is available preceding the year in which the insurer became insolvent or, in the case of an assessment with respect to an impaired insurer, the calendar year for which information is available preceding the year in which the insurer became impaired bears to premiums received on business in this State for the calendar year by all assessed member insurers.

C.__Class B assessments, as described in subsection 2-A, against member insurers for each account must be in the proportion that the premiums received on business in this State by each assessed member insurer on policies or contracts covered by each account for the calendar year for which information is available preceding the year in which