There are many things which could wrong with such a survey,
e.g.
"Statistically this means one percent of all stars should have such planets. It ís estimated that the orbits of 10 percent of these planets are tilted edge-on to Earth and so transit the face of their star."

This is an obvious contradiction.

I would say that all stars have planets, unless some process removed the planets, that would "normally be there.

Unless we don't understand star formation or there are types of star formation we don't know of.

One way of stripping a star of planets would be if a sun was ejected from a solar system. Say in a situation where there 3 or 4 stars in a solar system. Or a situation where star system "collide" with other star systems- such events might more common during periods when galaxies collide. Or it might more common near galactic cores and/or interaction with galactic black holes.