You can look at the income grid to check that the extra income from your wage increase does not change the part of the grid that you are currently in.
If it doesn’t change then yes, this is right, your discount stays the same and the amount of council tax you need to pay won’t change so you won’t receive a new bill with more or less to pay.
For example, if you are currently receiving a 75% discount as a couple with no children in a household and you and/or your partners net income increases from £190 to £220 per week, then your discount will stay the same as it still falls within the £175.01 to £225 income band.
The new scheme is designed to be simpler and prevent small changes in your household income causing the amount of council tax you need to pay to change every time.