I had the same type of question about a 6" jointer I was considering buying from Grizzly. While I realize that I was asking for information on a different tool, it seems to be Grizzly's policy is to provide the maximum draw of a machine on their specs. Here is the email response I received from them.
...Thank you for contacting us with your questions. A 15 amp dedicated circuit is recommended for the G0604 Jointer. Also, a 15-amp dedicated circuit is recommended for the G0452 Jointer.
The 15-amp breaker in each circuit will provide the most protection for each machine. Each breaker should trip when the machine on its circuit is drawing approximately 15 amps for a period of time.
Since the motor on the G0604 should not pull more than 13 amps, a 15-amp dedicated breaker would provide adequate protection for this machine. Also, since the motor on the G0452 should not pull more than 14 amps, a 15-amp dedicated breaker would provide adequate protection for this machine. The proper 15-amp dedicated breakers would allow each machine to start and run properly.
Grizzly's responce is rather puzzeling. They perceive the breaker as being a protection to the machine, not your shop's wiring and possible fire hazzard. This is similar to some information that I found in my SawStop manual. I would say that based on the response I got from them a 20 amp circuit would be fine for you. If you're not sure, give Grizzly a call or send them an email like I did. That will give you a definitive answer from the source, not speculation from me.
Since I just had a new 220 circuit installed in my shop, I can understand that there is a big difference in cost due to the current high price of copper. Because of some savings I was able to provide to my electrician by rerouting the wire and providing some of the material he needed, he installed a 30 amp circuit for the same amount he quoted me for a 20 amp, but he's done a lot of work for me and we get along wery well. Your experience may differ.