It's usually me that spots the changes.
Ordinarily, the Accesso booking page doesn't get updated until accurate information is known, so once something is on there it should be as reliable as can reasonably be. The reason being, it is literally forming the contract between guest and operator. It's also why other operators who do not know their precise details, won't sell tickets until they do. Disney typically only publicly announces operating hours upto 3 months in advance, so that when they are announced, they are accurate.
Whilst attraction availability can never be guaranteed due to reliability or unforeseen consequences, stating the number of attractions that will be there is a lot more specific. Unless they have 5 mazes already signed off and ready to go, it makes no sense to claim how many mazes will be operational and sell tickets with that statement.