I bought a busy-base manual screen this week. When is is lowered it is not completely flat but has slight ripples in it. I admit I can't notice them when watching a movie but is this normal? It was £250 for a 2 meter wide screen with beaded glass material - should I expect it to be perfectly flat or not? Will this improve over time? The screen is mounted on the ceiling so I assume it is horizontal, any advice will be gratefully recieved. Also when it retracts I have to take the weight off it to stop the screen from locking before it fully retracts. In other words I have to help it shoot up as quick as possible. Does this mean it is defective?