Hi Suis,
You need to calculate the points for age, based on the age when you first applied and obtained the HSMP visa.
In one of the questions on the calculator where it asks whether you want to claim points for your age. If you click the help link (opens in a pop up), it shows following.
"Points-based calculator - help
If you are in the UK and are applying to extend your stay you can score up to 20 points for your age. You should use your age at the date of your application for your first permission to stay as a Tier 1 (General) migrant, as a Highly Skilled Migrant, as a Writer, Composer or Artist or Self-Employed Lawyer. Please refer to the Tier 1 (General) policy guidance for details of the points that you can score for age.
If your first application was to the HSMP this will be the date that you applied for your HSMP approval letter, not the date that you applied for your leave."
This clearly tells that you can claim points based on your age when you first applied for Tier 1 (not your current age).
Hope this helps.
Please below thread for answer on this and other queries related to earnings.
http://www.immigrationboards.com/viewto ... highlight=