from above sounds like not standard now but more common than in past
some changes may be 'necessary' by aman increasing sales & marketing
past example for aman sri lanka >
For bookings between 20 December 2011 and 10 January 2012...full payment are required 45 days prior to arrival and cancellations made during the 45-day period will result in a penalty of the entire length of stay. Reduction on the number of nights stay can be made within 30 days of booking. If the number of nights is reduced during the stay, a 100% payment of total stay is applicable.
venice is one of smallest most expensive amans, followed japan with adding some weekend premiums