How does this work?? (Get function)

Ok, I'm trying to make a component for a ship that adds 'space' to the ships hull (ie, tonnage). I call it 'External Hull Enhancement'. I've used the negative tonne forumula up until now (ie make a component that just subtracts away from the total tonnage so as to 'trick out' more space) but now I'd like to try using the 'Get_Vehicle_Size_Tonnage' function to add 20% of the hulls total tonnage back into the ship.

Question one: Would this mean that for each component it would re-calc the tonnage of the ship (ie, each successive comp would not be 20% of the original ships size added but 20% of the new total successively).??

Question two: Why does this not work (what dumb thing am I not doing, it keeps giving me a 'cannot parse' error when loading the mod.)
I figure someone with waaayyy more experience can answer this easier than I could figure out in probally 3 hours of racking my brain (while I chase my 3yr old around and try to give her a bath in between, lol, ..)
Comp:

Name := External Hull Enhancement
Description := Additions to the outside of the hull to increase the 'space' of a ship or base. (uses negative number formula).
Picture Number := 268
Maximum Level := 5
Tonnage Space Taken Formula := 0 - (0 + ((Get_Vehicle_Size_Tonnage("")) * 0.20))
Tonnage Structure Formula := 100 * (1 + ((Get_Empire_Tech_Level("Armor")) * 0.1)) * (1 + (([%Level%] -1) * 0.05))
Cost Minerals Formula := 500 - ([%Level%] * 25)
Cost Organics Formula := 200 - ([%Level%] * 25)
Cost Radioactives Formula := 300 - ([%Level%] * 25)
Supply Amount Used Formula := 0
Ordnance Amount Used Formula := 0
Can Be Placed On Vehicle Types := Ship, Base
Can Be Placed In Ship Sections := Armor
Component Type List := Technological
General Group := Vehicle Control
Custom Group := 0
Number Of Requirements := 2
Requirements Evaluation Availability := AND
Requirements Evaluation Allows Placement := TRUE
Requirements Evaluation Allows Usage := TRUE
Requirement 1 Description := Empire must have at least tech level 1 in Construction.
Requirement 1 Formula := Get_Empire_Tech_Level("Construction") >= (1 + ([%Level%] - 1))
Requirement 2 Description := There is a limit of four external hull additions per vehicle.
Requirement 2 Formula :=Get_Design_Specific_Component_Count("Space Yard")