How many contracts in futures are not fixed. If you open more orders, you may receive more orders from others (multiple orders change hands, and the total number of contracts remains unchanged), or you may open empty orders (double orders, contract increase 1 pair).
The same is true when closing positions. It may be that others open more orders, that is, they change hands (the number of contracts remains the same, and the total number of positions remains the same), or it may be that you buy short positions and close positions, that is, you are even. That is, the contract (position) has been reduced by two.