Does it mean that if I use the total value of 3 engineering command of a ship, I wont have anymore point value for the next rounds until the game finish?

For eg, the engineering value of a VSD is 3 points then I use all 3 points, the next rounds would be 0 point until the game finishes?

Or even if I use 2 of 3 points, does it mean I only have 1 remaining point left to spend for the rest of the game?

Neither.

It means if you, for example, had Eng 3, spent a token and a dial, gained a total of 5 points, and then spent 4 (2x2) on 2 raused shields.... that one excess point is lost - it will not carry over for the next time you do an Eng command

SO if the next time, the next round, you did another eng command, this time with just a dial at eng 3, you would gain 3 fresh points.... but any you don’t spend right away are gone.

Thanks for the info xD