Since you are coloring by row, setting the uitable's BackgroundColor may work for you.
You can use a matrix of colors. Example:
figure
t = uitable('Data',randi(10,4,3));
t.BackgroundColor = [1 0 0; 1 1 0; 0 1 0; 0 1 1];
If the table has more rows than there are rows in BackgroundColor, then the colors are repeated as necessary:
figure
t = uitable('Data',randi(10,4,3));
t.BackgroundColor = [1 0 0; 1 1 0; 0 1 0; 0 1 1];
t.Data(end+10,:) = 0;
Alternatively, you may be able to speed up your code that uses addStyle if you make sure to removeStyle any uistyle when it is no longer needed.
