different behaviour for hide spans in header and rows

[jaapandre]

In table settings you have the options to hide spans, if checked it shows duplicate string in consecutive rows, very useful if you export the table to excel, but the strings in the header rows is also repeated. This doesn't looks nice. In the first attached file I would only want one string 'Line' in a spanned top left cell

So like this:

I have no preference for repeating the year (maybe a slight preference for not repeating)
So the green part of the second table should also be the green part of the first table.