Yes, the typical upload speed is 40 Mbps because of the 20% over provision. 20% of 35 is 7. 7 + 35 is 42, 42 minus the TCP/IP overhead gives you roughly 40. The marketed upload speed is 35 Mbps.
They list the typical download speed as 1036, even though the vast majority of people out there are limited either by their modems 1 Gbps port or 1 Gbps port on a router, switch or NIC and won't see significantly more than 940. I have one of the modems with a 2.5 Gb Ethernet port and when connected to my 10 Gb NIC I top out at 1180 Mbps down, as the download is provisioned at 1200 Mbps, 20% over 1000.