CMS VDN Report loosing ACD calls

[SirArthur]

Hi,
I am facing following issue, that it seems that I loose ACD calls in the statistic:

% in Service Level = 86,96

ACD Calls & Connected Calls = 22
20 of them are in the defined Service Level ===> so this should be 90,90 % (100*(20/22)).

If I calculate (100*(20/23)) then there is the right Service Level.

But where do I loose this ACD call? Unfortunately I have this conditions on all VDN reports.

Thanks in advance.