Reports on Planning and real work mix up real and planned work (?)

In the reports belonging to the Planning and Real work sections, the planned and real work are treated as equivalent, and added up column-wise and row-wise.

Why is this so?

At least for the past dates, we know whether the resource has worked as per plan.
(Assuming that he has updated whatever work he has done on a daily basis).

So, of he has not entered any work hours for a day in the past, then it should be counted as zero.
Instead, the original planned value is retained and used for the summation.

This would create a mix of real and imaginary work.
For example, PFA screenshot taken on 27th June. It shows four (imaginary) resources.
If you see the past week (22nd June onward), the cells show a mix of planned and real work.
As a result, the summed values are also a mix of planned and real work.

So why not keep two separate rows, to add up the planned and actual work separately?
Also, what is meant by "not planned work"? How is this derived?

BTW there is no context-sensitive help on this. Please include a full page!