No, that would not be considered a lifting surface. To be considered a lifting surface, it must contribute lift to the overall flying assembly. An easy way to demonstrate that would be to demonstrate flying it with and without the surface, if the surface is not present then the flight would be significantly different.
The Load Scored Bonus is awarded only if the tower is outside of the 29.0 cm diameter circle through the entire testing. If the tower sags inside of the 29.0 cm circle during testing but the bucket remains off the ground and the tower is still outside the 20.0 x 20.0 cm opening on the Test Base, testing will continue until failure occurs as defined in the rules.