Difference between SetText and TypeKeys for a DomTextField

Running SILKTest 19.0 using 4test.

I have a DomTextfield that has a max limit of 64 characters.

If I use the routine TypeKeys and attempt to enter more than 64 characters, only 64 characters will be written as to be expected.

If I use the routine SetText and enter more than 64 characters, all of those characters will in fact be set into the DomTextField.

Can someonetell me why this can occur?

Thanks,

Phil