Yes, you need to be careful with data rate units because they can be confusing (a capital B and a lowercase b mean different things).
For example, at home I have a download speed of 30 Mbps and an upload of 3 Mbps.
That's equivalent to about 3.6 MB/s or 0.4 MB/s (some pedant will probably now chime in to say that should be in MiB/s!)
So a single layer DVDR would take me 20 minutes to download, or 3.5 hours to upload.