hello
my super avenger change the date 7 min before midnight.
is it normal?

Very normal. You will find that's actually pretty good for a 7750 movement!

update:
last night it was changed 2 min before midnight.

It's hardly worth the effort. The movement must be uncased, the mainspring let down, the hands removed and the motion works adjusted to the precise point where the date changes. Then the hands must be precisely aligned with the 12:00 marker and installed without moving the motion works. This might need to be repeated once or twice to get it exactly right since there is some backlash in the motion works. Finally, the movement is recased and tested for water resistance integrity. Obviously, we all try to reassemble the movement with this thought in mind, but a minute or two either way is acceptable; and I'm pretty anal about movement reassembly.

And don't forget that Breitling hads are designed to be single use so you may go through 2 or 3 sets of hands just to do it.