This means that this real-time data is triggered by the list of long positions (C), and the number of long positions is lower than that of short positions and long positions previously hung.

The transaction volume of this empty order is 10 lot. Because the amount in futures is calculated in both directions, the short position (B) is 5 lots, while the long position (C) trades 5 lots with it, and 5+5 =10;

The position difference is also the position change triggered by this transaction. This position does not refer to the change of your personal position, but the change of the position of the whole market caused by this transaction.

Therefore, there are only 5*2 lots of Masukura, one is short Masukura (B) and the other is long Masukura (C). I think the original assumption may be that there are not only four people, but also other people in the market, that is to say, A is a long position, and there must be a short position that has traded with A, that is to say, there are 1*2 hands to lighten the position, including A's long position and another short position, so the position difference is 10-2=+8 hands.

The latter is easy to explain. D is a bull with 2 lots, and B is a bear with 2 lots because of trading with him, so the spot transaction should be 2+2 = 4;

And the position difference: because no one has closed the position, the position difference is the increase of D and B, that is, 2*2=+4 lots.