Hi TG,
MI10 - Input counter qty which is book qty.
MI03 - Display Inventory document which is the different qty (based on counter qty and stock qty)
MB5B - keep in mind for selection screen (many options), you can drilldown the GR or GI amount to see the real posting qty during MI10.
if you can provide us the MI03 document overview info and confirm what qty input during MI10, I can check further.
hope it can help.
thx.
Pedro