I have been hesitating to answer because answers that start with "NO" are not very usefull. Well here goes.
No, the colors can not be slid down automatically.
If you are inserting the new lines at the top because you want to have the new entry visable, this can be done by inserting at the bottom.
The "index values" property will let you scroll the table to keep the last row visable after each row is added to the table.
If this acceptable, you will only have to update the colors for the cells in the row you are adding, but you would have to do this for adding at the top so no difference there.
Ben