Hi Aldrin,
if you need to work with Element ID, it's pretty bad idea to use ID.Low only, because in such case you work with incomplete Element ID! ... and it means the only fact you can say about such code is it will not work correctly with some design files.
In VBA the element property ID is DLong (which is 64bit integer) and if you use ID, you should always use DLong.
In C# the property ID is long, so the correct code is:
long elementId = el.ID;
With regards,
Jan