That doesn't mean anything. The vertical beamwidth of those panel aerials is very tight. Sometimes only 5-10 degrees. If that tower is more than a few stories high you're looking at quite a distance before you're in the aerials 'sweet spot'. With aerial gain it's quite possible you're associated to another tower that's further away, possibly not even line of site, but due to the gain of the aerial (up to 13 dB on some types) you get a stronger signal and that's the one phone choses to associate to.

You can observe this effect (albeit slightly exaggerated) in Piccadilly Gardens. The Sunley building has all the major providers up there, but because they're on the top and the building is 30 stories high, the surrounding area is a blackspot for cellphone coverage because the aerials are actually firing off into the distance and the signals from other base stations further away are weaker and also affected by multipath problems due to building clutter in the locality.