iTunes with FCP

FCP 6.0.5

I bought two songs from iTunes, imported them as is into FCP. I put them on the TL, renderd as they had a red line above them, and they play fine. I also converted these two songs into AIFF, 48Khz and imported those back into FCP and they play fine on the TL without a red render line above them as the original songs had. If they play in FCP will they play on a DVD? I've heard that some people could not play music they purchased from iTunes but I seem to be able to do that.

Any comments?

Tom