Macro to Identify Largest Value Across Columns, Then Subtract Value Held in Other Cell

I need a macro to identify the largest value across columns I2 - AS2. Once found, I need to replace the value with value found minus the value in BQ. The final step would be to highlight the cell that was changed across columns I2 - AS2, then move to the next row and do same until I reach the last row in the worksheet. The number of rows vary each day but the columns do not.

I have written the attached code, which identifies the largest value in the first row, but I don't know how to replace the value found with the new value and then move to the next row until it reaches the final row for the day.

In the attached file, my largest value sits in AC2. That value needs to be replaced with 486.17 (1,175.37 - the value in BQ2 of 689.20). The cell should then be highlighted so I can quickly identified what cells have been changed.

Any help would be appreciated.