Puzzling: some units at "100% affordable" 535 Carlton are somehow labeled 549 Carlton

I wrote in March about how two middle-income units at the "100% affordable" 535 Carlton building were listed on StreetEasy with discounts.

Those units are still available:

• a two-bedroom, two-bath unit, at an announced $3,223 rent, with one month free, generates a Net Effective Rent of $2,954
• a studio at an announced $2,137 rent, with 1.5 months free, generates a Net Effective Rent of $1,870

A look on the 535 Carlton web site, however, shows not only those units but eight more apartments at the same building, though listed as 549 Carlton: 

• one studio, listed at $2,137
• five one-bedrooms, listed at $2,457
• two two-bedrooms, listed at $2,954

Other than the studio, which does not imply a discount, the other two represent a Net Effective Rent, with one month free. 

(There's also a studio listed for the other "100% affordable" building, 38 Sixth, though no rent is listed.)

It's not clear to me whether those listings are artifacts of previously rented units, or whether they are an alternative way to market units.

The use of the 549 Carlton address is puzzling. 

Could it be a way to "refresh" the image of a building that's been known for having trouble filling its units? Given that the units appear on the 535 Carlton web site, they're not fooling anybody.