uvm_reg_map get_reg_by_offset() is misleading

While playing with UVM_REG we noticed that the behavior of uvm_reg_map::get_reg_by_offset() is inconsistent. Here's a code example of what I mean:

class some_block extends uvm_reg_block;
  some_reg my_reg;

  virtual function build();
    // ...
    default_map.add_reg(my_reg, 'h10);
  endfunction

endclass


some_block my_block = new();
my_block.default_map.set_base_addr('h100);

offset = my_block.my_reg.get_offset(); // offset will be 'h10
my_reg = my_block.default_map.get_reg_by_offset(offset); // my_reg will be null
my_reg = my_block.default_map.get_reg_by_offset(offset + 'h100); // my reg will not be null

What I mean by inconsistent is that the meaning of 'offset' is different for 'add_reg(...)' and for 'get_reg_by_offset(...)'. By just passing the offset to it, it doesn't find the register, but by passing it the offset plus the base address it finds the register. Shouldn't get_reg_by_offset not care about the address map's base address?

The code above is just a snippet. The full code is available on EDAPlayground: http://www.edaplayground.com/x/3Z7