Hello Luis Fernando,
It certainly looks like a documentation error.
In this case, the Figure 4-1 from the Reference Manual shows the correct information:
MC9S08AC60 FLASH Size: 63280 bytes.

I based my response on its corresponding .prm file:
ROM = READ_ONLY 0x1860 TO 0xFFAF;
ROM1 = READ_ONLY 0x0870 TO 0x17FF;
Hope this information will be useful for you.
Have a great day.
Best Regards,
David Diaz.
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