Like my other post, how exactly is latency going to change? SAT3 uses fibre. Seacom uses fibre. They both travel at the speed of light and you are sitting on the opposite side of the planet to your EU game server. You will only see a difference in time it takes to route from the landing site to your server, and quite frankly, that is where your lag is coming from.
Look at the stats they posted yesterday, 60 to 70ms one way from Seacom here till endpoint, double that because you need your data to get back here. At a minimum you have 150ms latency. Take that away and you end up with the 100 or so that people in the EU get.