Ping isn't real time, it refreshes every second or so. If your net is a little unstable but usually fast it might just be recording your ping as it spikes which wouldn't be noticeable ingame. It might be that you get faulty readings because of your port issues Seeme. It might read 800 but is probably 200-400 in reality.
Ping isn't all that important anyway. The important thing is stability. For instance, if someone has 500 ping but is perfectly stable your orders may take awhile to be reached by your units (half a second instead of instant) but the game will run fine. If instead they have 300 ping but shitty net, orders will reach your units but the game will stutter and lag.
Ping can only be reduced by getting better net (only affects it slightly), opening ports that may be blocking traffic or physically moving closer to the host which obviously isn't feasible.
