conor - 10:29 am on May 17, 2010 (gmt 0)
As Tedster pointed out there is strong evidence that tweaking keywords in titles too often can lead to ranking problems and I was concerned about this too.
After much thought though we concluded there there was a huge difference between manipulating keywords in a title and modifying a number which ultimatley improves the user experience.
If the numbers are not going to increase wildly (digit wise) then there shouldn't really be an issue.
As always it's best to test these things on a small percentage of your pages first...