Just a quick one - again

As a very careful person (should have had a Scottish father and a Mother from Yorkshire really!!) - I am paying for residency and have decided to buy a
Mondial 100 UKH at 1690 YTLI don't want a helmet (we have taken over good UK ones) - the bike doesn't need taxing - but I want a box on the back.
The dealer is saying
1690 + 200 YTL for box + registration and compulsory insurance - but should that not be less as most people I know paid + 200 YTL for bikes that needed tax and they got a helmet and a box - so I should be 200 YTL - LESS allowance for Tax and Box??
It all adds up - as I keep telling Gill - my savings will pay for more visits to the Mozaic Bache

:D:D
Anyone know - so I can be firm - or do I accept it???