penalty question

I was wondering if anybody could help answer a question for me. Is offensive holding in the NFL a spot penalty? I know that holding behind the line of scrimmage is marked from the previous spot, but what about blocks downfield. I am asking specifically about Rice's run that was called back. The original line of scrimmage was the 24, and the hold on Gay happened at the 32. After the call, the ball was respotted at the 24 for a 1st and 10. When Starks was called for holding, it resulted in a 1st and 20. Through the years, our receivers have been called for holding and it seems that all infractions were marked from the previous spot. Any help you can give me would be greatly appreciated.