(a) Except as provided in subdivision (b) of this section, the cost of any aircraft proposed to be acquired shall not exceed, as of the 31st day of December next preceding, the sum of:

1. (1) ¼ of one percent of the insurer's admitted assets up to and including $500,000,000; plus

2. (2) ⅛ of one percent of the insurer's admitted assets in excess of $500,000,000.

   Should the cost of an aircraft exceed the amounts set forth in paragraphs (1) and (2) of this subdivision, it shall nevertheless be allowed as an admitted asset up to and including the amounts as determined in this subdivision.