I've had my Ralliart for about a month now. When I first got it it would run at higher rpms. Usually driving in town I would go 50-60kmh and I would be low 6 gear are high 5 gear. Today on my way home from work i noticed I was revving lower. I was in 5th the whole time and it even shifted to 4 once for a bit. Why is it doing this?