I believe you can specify under 28 as your age was 26 at the first grant of leave as HSMP as per UKBA ploicy and law, attributes section:
http://www.ukba.homeoffice.gov.uk/polic ... appendixa/
33. if the applicant was first granted leave in the categories of Highly Skilled Migrant, Writer, Composer or Artist, Self-employed Lawyer or Tier 1 (General) Migrant and has not been granted leave in any category other than those listed here since the first grant of leave, points will be awarded based on the applicant's age at the date of the application for that first grant of leave. if the applicant has been granted leave since his first grant of leave in a category not listed in this paragraph, points will be awarded based on his age at the date of application for a grant of leave in a category listed in this paragraph where leave has not been granted in any category not listed in this paragraph between that grant of leave and the current application.
