The only benefit you would have of using a static IP is if you were monitoring your stake's connection from a third party location, ala your home, your work, etc. However, such monitoring is likely overkill, and may possibily be interpreted as hostile network activity (constant pings, traceroutes, etc.). I'm not yet familiar with the firewall ruleset, so it may be that such monitoring would not be possible.
Most of the time, dynamic IP's are based on a DHCP lease anyway- the one my ISP uses is a 7 day lease. If the IP was on a machine (router, firewall, PC, etc.) that was constantly powered, your lease would not expire and you'd have the same IP for months, if not years. Depending on how their DHCP is set up, even on losing the lease, your 'new' IP address may be the same as your old one.