ZG76 Claims on 1 September 1940

[Peter Cook]

In The Luftwaffe in the Battle of Britain, 1980, p. 71-4 Armand van Ishoven, has a chapter titled '500th Victory' in which an unnamed war correspondent describes the 500th 'victory' by Bf 110 unit ZG76 – which claimed its first victory on 1 September 1939 and its 500th one year later on 1 September 1940. It states that the Geschwader started the day with 483 victories, and then took part in escorting bombers on an airfield attack near London. It is well recorded that I and II/ZG76 was part of the escort for Do 17s of I and III/KG76 on this day, and several sources list 8-9 claims for Spitfires and Hurricanes, all by 6/KG76. But van Ishoven's account goes on to state that I Gruppe claimed seven, II Gruppe claimed six, and III Gruppe claimed four, for a total of 17 claims for no losses, reaching the total figure of 500 for the year.
As stated above, several sources, including Tony Woods OKL claim listings, identify 8 claims, while Simon Parry identifies a 9th – all by 6 Staffel. Is there any basis for the 17 claims described by van Ishoven?

Peter