Mixed grades means that games will be alocated in a way that grades will be mixed, while keeping both teams reasonably well matched. Some games will be more competative than others.
Example 1.
Team A - 1 x Grade A , 1 x Grade D+
Team B - 1 x Grade C+, 1 x B-
Example 2.
Team A - 1 x Grade B, 1 x Grade B-
Team B - 1 x Grade B+, 1 x Grade B
Similar grades means that all games in this session will be of variations of similar grades. If you are a grade B Player (B-, B, B+) then all you games will be with the most similar graded players, often in a round robin. Depending on participation, games might require larger variation in grading.
We undersatand this request, however, by its very nature, the 'better' players are then having to play with you, who is by definition of the request, not as good a player. On our mixed grade sessions we endevour to facilitate these requests, but we will attempt to make team pairings as even as we can and games will vary throughout the session.