Yes, that's what I mean. And yes, it does roll back 4k. Try downloading anything and stop it whle it's still under 100k (for easy viewing) ... watch what it's stopped at. Then resume it. You will see it start 4k under where it was before. But 4k can still have bad downloads, so 10k would really be preferable. And unless it's hard-coded, it should be editable.
Note that the RESUME command *DOES* accept a resume-from file point, so it should be editable as an option.
