Hi Mike,
I downloaded the trial of 5DtoRGB from the app store. Version 1.5.8. We seem to read the timecode correctly as far as I can tell. The timecode track is written with 24000/1001 which is a valid 23.976 timecode and we pull it in correctly. What version are you using?
Of note, it seems one of the reasons people use 5DtoRGB is because it knows how to read the full range yuv out of the 5D footage. Just to be clear you get the same results using Premiere/AE or Adobe Media Encoder. We read full range 601 YUV out of the 5D movies so if you needed to transcode you could also use AME and get the same results.
Cheers
Dave