It gave the plans a four out of five score for their risk of not going ahead, up from two in March.
The project has proved controversial among local residents, with many objecting due to the potential impact a new building would have on the heritage of the area.
Saltaire was built in the 19th Century by the industrialist Titus Salt, who constructed homes for his workers alongside the mills they were employed in.
It was designated a World Heritage Site in 2001.
Others objected to the loss of a car park in the centre of the village.
A petition calling for the council to revisit the planning application has now been signed by more than 1,500 people.
According to the document, a £7m scheme to redevelop an unnamed site in Shipley was also at risk of not going ahead, with that project given the maximum rating of five.
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