Hum, I think you are right. I just (unsuccessfully) finished biding for Amsterdam. I did the following bids:
$ 100 4* Joordam - Canal Best West
$ 110 4* added re-bid zone
$ 120 4* added re-bid zone
$ 100 4* Royal palace - Central Station - Dam Square
$ 110 4* added re-bid zone
$ 120 4* added re-bid zone
$ 100 4* Canal Belt East - Plantage
$ 110 4* added re-bid zone
$ 120 4* added re-bid zone
$ 100 4* Museum Quarter - Vondelpark
$ 110 4* added re-bid zone
$ 120 4* added re-bid zone
$ 130 Joordam - Canal Best West, Royal palace - Central Station - Dam Square
$ 140 added re-bid zone
$ 150 added re-bid zone
$ 130 Royal palace - Central Station - Dam Square, Canal Belt East - Plantage
$ 140 added re-bid zone
$ 150 added re-bid zone
$ 130 Canal Belt East - Plantage, Museum Quarter - Vondelpark
$ 140 added re-bid zone
$ 150 added re-bid zone
$ 130 Museum Quarter - Vondelpark, Joordam - Canal Best West
$ 140 added re-bid zone
$ 150 added re-bid zone
$ 160 Joordam - Canal Best West, Royal palace - Central Station - Dam Square, Canal Belt East - Plantage
$ 170 added re-bid zone
$ 180 added re-bid zone
$ 160 Royal palace - Central Station - Dam Square, Canal Belt East - Plantage, Museum Quarter - Vondelpark
$ 170 added re-bid zone
$ 180 added re-bid zone
$ 160 Canal Belt East - Plantage, Museum Quarter - Vondelpark, Joordam - Canal Best West
$ 170 added re-bid zone
$ 180 added re-bid zone
$ 190 Joordam - Canal Best West, Royal palace - Central Station - Dam Square, Canal Belt East - Plantage, Museum Quarter - Vondelpark
Tomorow I will try again.