Before you do that, you should get in touch with the vendor and find out about the details...

It may be a mistake.  I had a similar issue. The readme file in Empress Biata by Reciecup says that it's only for non-commercial use, which it doesn't say in the renderosity licence. I contacted her about it, and she told me it was a mistake in the readme file or something to that effect, and that it can be used for commercial renders.