opposite direction waves are out of sync?

ok, so im working on a lighting profile and i want two waves to cross in the center of the keyboard, but when i set a wave to go at 270 degrees it doesn't start in the same spot as the wave going at 90 degrees. the waves pass each other on the left side of the keyboard unless i set the time different but then they either don't cross at all or they cross at a random spots. i am using a huntsmen v2 tenkeyless, but i ran into the same problem on my ornata chroma when i tested it. any ideas on how to get them to cross in the center every rotation?