the 18 point font is in the latest revision to Reg Z and became effective Oct. 1, 2001.
See § 226.5a Credit and charge card applications and solicitations. Specifically, 226.5a (b)(1) Annual percentage rate. Each periodic rate that may be used to compute the finance charge on an outstanding balance for purchases, a cash advance, or a balance transfer, expressed as an annual percentage rate (as determined by § 226.14(b)). When more than one rate applies for a category of transactions, the range of balances to which each rate is applicable shall also be disclosed. The annual percentage rate for purchases disclosed pursuant to this paragraph shall be in at least 18-point type, except for the following: a temporary initial rate that is lower than the rate that will apply after the temporary rate expires, and a penalty rate that will apply upon the occurrence of one or more specific events.