Strength bug with Superdom?

[radioactive28]

Found Superdom recently and got hooked - so much so that I went to take a look at the source code because I thought one aspect of the behaviour made no sense.

In the game, when the power/strength is calculated for each tile, tank-farm and plane-factory pairs on a tile has no effect on the power (i.e., a tile with a farm does not get a power boost when a tank is added to it).

Looking at the code, it was written in such a way that a tank's power is bypassed when there's already a farm on the tile, and a plane's power is ignored if there's a factory on the tile.

Is this supposed to be correct?