Merops often shows large tracked changes, to help you be aware of why Merops made the change, and to enable Reject Identical Changes to work. So an inserted space in a unit expression is shown like this '8kg kg'.
If you'd rather changes were as concise as possible, you can now click Shrink Tracked Changes on the Merops Ribbon (on the Merops Main toolbar in Word 2003 or earlier). Merops will then shrink tracked changes where possible in the active document, so the example above will become like this '8 kg'.
Some people may find that clicking this once before editing each document makes it much easier to review. However, please be aware that the Reject Identical Changes tool will be less useful, because it works by comparing the inserted and deleted text, and an inserted space is not enough information for you to want to reject all instances like that.