Understanding PIC MCU memory from datasheet
As an answer, yes you have spotted an error in the PIC12F1552 data sheet.
The graphic for TABLE 3-3 should look like this:

And yes, there is 256 bytes of RAM in the PIC12F1552 but only 240 bytes can be accessed using the linear address space.
The 16 bytes of Common RAM are not part of the linear address space.