[PvK]

Unfortunately, planetary bombardment damage assessment has always been severely retarded. I believe the actual order, is more or less "the units with the lowest amount of structure per unit die first, and before any facility damage." (I could be more precise, but that's essentially it.)

So, if your WP's have more structure per unit than your troops, the troops get hit before the WP's.

If you build larger troops than infantry, though, and use shields and armor, they will probably have more structure than a WP, and so they won't get killed before the WP's, so an invasion attempt will encounter the troops.

I despise that bombardment damage allocation system BTW, and have complained about (as have Baron Munch. and others) it several times over the years - it's really lame.

PvK