@Chief:
Not easy to explain, but:
In the European Community Holland is standing alone in having a special tax for cars and motorcyles. Apart from the 'normal' buying tax, those vehicles get another 42% 'special' tax over the price-with-'normal tax'.
Also passenger vehicles have to pay road tax. It depends on the kind of fuel how much that road tax is. road tax for Petrol driven cars is relative cheap, For Diesel and LPG cars very expensive. The fuels themselves differ the other way around. Petrol being expensive, diesel and LPG being cheaper.
So far so good.
To promote business the Dutch gouvernement decided to lower the road taxes for vans and pickups and skipped that special 42% 'special' tax!
But by doing that guess what: everybody rebuilt their cars to transform them to vans or pickups!
So there came rules to prohibit not correct use of the lower tax regime. And those rules are very unlogical, beiing only there to stop unlawful use.
So every car which wants to use the mild tax regime has to be measured. Both the cabin and the pick-up part. The pick-up part may not be entered through the cabin, and the size op the pick-up part has to have special dimensions. The Avalanche has 3 cm too less space in the pick-up part, and it is too easy to enter the pick-up part.
So:
1 we have to close the pick-up part from the cabin.
2. we place a screen 3 cm in front of the midgate. The precise wording in the Book of Rules states then that 3 cm of space may be added on the space of the pick up part! Voila!
Don'ask me if I like it

, but yes it saves me ten thousands of Dollars!
Now I can drive my car on LPG, being the cheapest fuel here in Holland, without significant road tax.
OK, Looong story, next time I will be shorter!