The same error is on the employer's CD-ROM. The Internet version of the booklet was corrected earlier this year.
The error appears in the table in section 43 'Cars with a carbon dioxide emissions figure first registered on or after 1 January 1998 only: ready reckoner' on page 14. The entries for cars with 170 g/km of emissions read '20%' and '21%' when they should read '21%' and '22%' respectively.
The same table is reproduced in appendix 2 of leaflet 480 but shows the correct figures.
HMRC say that for cars made available in 2007-08, with emissions of between 170 and 174 (g/km), employers should use 21% as the appropriate percentage when calculating the figures for entry on forms P11D after the end of the 2007-08 tax year. For the same cars made available in 2008-09, employers should use 22%.
If employers used the incorrect appropriate percentage of 20% for cars made available in the 2006-07 tax year, HMRC ask that they write to their local tax office telling them about the error. HMRC say that the employer will also need to tell the employee the correct cash equivalent of the car(s) and any fuel for cars.