I found this script a couple month ago..
Is there a chance to tweak it so i can change the value for all/both keyframes?

keyNumToChange = 2; //change this - the key num to change(numbering starts at 1)
newVal = [value[0],100]; //change this - the new size.
target = transform.position;
//-------
nearKey = target.nearestKey(time).index;
lastKey =(target.key(nearKey).time>time) ?((nearKey>1) ? nearKey-1 : nearKey) : nearKey;
nextKey =(lastKey