Scott Stringer (Getty, NYC Comptroller, iStock/Illustration by Alexis Manrodt for The Real Deal) Mayoral hopeful Scott Stringer wants to require all residential projects to include affordable housing — but some developers say his numbers don’t add up. The city comptroller released a 47-page housing plan Thursday including details on the “universal affordable housing” program he announced last year. Under it, developers would have to make at least 25 percent of apartments deeply affordable in projects with 10 or more units. The low-rent units would be affordable to households earning, on average, 60 percent of the area median income — significantly less than in Mayor Bill de Blasio’s housing plan. Developers would get subsidies and tax exemptions to build in neighborhoods where residents earn below 60 percent of AMI.