In the Official interpretation of Section 1030:4(b)(1)(I) for Rate Disclosures it states that if an annual percentage yield is the same as the interest rate, institutions may disclose a single figure but must use both terms. I have not seen this done.
Is it acceptable to use this method for tiered account disclosures?
1030.4(b)(1)(I)-3. Tiered-rate accounts. Each interest rate, along with the corresponding annual percentage yield for each specified balance level (or range of annual percentage yields, if appropriate), must be disclosed for tiered-rate accounts. (See Appendix A, Part I, Paragraph D.)
I think as long as you are meeting this requirement it should be fine to combine them as you referenced above.