Insurance after the Chipping

A few weeks ago I left my TT Chippen. After I have registered everything and also informed the insurance (AXA) of the changes, today there is a letter from the AXA in my mailbox that takes off my shoes. Before the Chippen: 198€ per half year with full caso After the Chippen: 368€ per half year with comprehensive I mean to have read here in the forum that only a possible added value of the car is insured!? Does someone have a few infos or tips like it with you looks?