MIRO Subsequent Debit issue

Hi,

I am posting subsequent debit in the MIRO and getting u201CError messageu201D

Below are the details of what have done till up to..

1) Limit PO created for 1000 GBP

2) GR Posted for 600 GBP

3) Invoice posted for 600 GBP

4) Subsequent credit posted for 200 GBP

again. One more

5) Subsequent credit posted for 200 GBP

Now I am trying to post

6) Subsequent Debit for 200 GBP and system is not allowing to post

Getting below error

Tolerance limit of only 25 GBP will be allowed

7) If I am going to post Subsequent debit for 400 GBP there is no error

Wanted to know, is this std one or is there any setting is missing

Thx,

jai