Chapter 12, page 12
The situation in Core Reading is that there is a single tax payment each year based on the total coupons paid in the previous year.
eg, in 2011 two coupons might be received in June and December, say, and the tax on both of the coupons is paid at the same time, say in April 2012.
For a bond with regular coupons, based on the above example, then there would be two coupons paid each year, needing a (2) annuity, but there would only be one tax payment each year (so no (2) on the annuity).
In the example following this part of Core Reading, the income tax is still deferred (ie paid after the coupons are), which is the topic of this section. But the situtation is different. The tax in this example is not paid in a single installment, but instead is paid four months after each coupon. So there will be two coupon payments each year, and two tax payments. Hence the (2) on the annuity for the tax payments.
The example is there to illustrate that you can get different situations described to you in the exam, and you have to read the question carefully to work out what to do.