System level uvm_reg_map::get_n_bytes() returns 0?

[Logger]

Why does uvm_reg_map::get_n_bytes() return 0 if you call it on a system level map?  That is completely useless and tells me nothing about the system.

 

If on the other hand, I call uvm_reg_map::get_n_bytes() from a lower level map in my register model, then I get the narrowest bus width in the map hierarchy.  That makes sense.  It seems I should get that same value when calling get_n_bytes() on the system level map.  Returning 0 is not useful under any circumstance.