I did something like this and it worked rather well.
Based on items With A Specific Value:
total of 'TotalPrice' where 'Price' has a value of '4.95' 'times' '.7474747474'
I know the decimal might be affected but added up to 5000 items in the cart and the price remained at 1.25. It took me about an hour to figure it out thou. Thanks for your response Jason.