Hello,
Interesting topic!
I can't find any 10o Gruppo losses at all on 17 June. They were however in combat with P-40s and Bostons in the Sidi Rezegh area. At least Franco Luccini (
http://surfcity.kund.dalnet.se/italy_lucchini.htm) claimed one P-40 and Angelo Savini (
http://surfcity.kund.dalnet.se/italy_savini.htm) claimed two more.
Italian sources gives the loss of Alessandri to the 2 July 1942 (the last pilot from the 4o Stormo to becom PoW).
Regarding the misidentification of the P-40 versus the Spitfire, this was quite common, at least as far as my own research.
Best wishes/Håkan