If I switch production on my starport do I lose the extra shields? That is, say i was almost done with a huge ship or anything that would take many weeks to build, and i switch to something that takes substantially less time so that the planet screen shows that the ship is now complete, does the extra production get aded to the next ship that is to be built?

I guess this might also apply to invading a planet where you get to use the production already used by the AI before you took the planet. Sometimes thers enough there to have a constructor on my next turn. Since I'm unsure of this i always make sure i choose a ship that will still show some weeks to go, so i dont lose and production.