You can call it D+5 but in terms of statistics it is almost meaningless.
Two polls: Set 1: D 45 and R 40, Set 2: D 35 R 30
Both samples are D +5, right?
But Set 1 contains 12.5% more Ds, while Set 2 contains 16.6% more.
The tricks of pollsters and statisticians are almost limitless when you start weighting and moving around demos (age, women, race, education).
There was an old saying back in the days where businesses were run through Excel and Lotus . He who owns the spreadsheet wins.
Same applies now.
Please see post 111 in response to your post