A question about Hans Rudel's unit

[Stuka Pilot]

I googled many infos including Wikipedia shows that Rudel was in I/StG.2 in Apr 1940 and transferred to III/StG.2 in Aug 1942(e.g:http://www.pilotenbunker.de/Stuka/Rudel/rudel.htm). Well, in Rudel's autobiography "Stuka Pilot", i found sth confused.From his words i get the meaning that before 1942 he had been transferred to III/StG.2.

Here is a passage quoted from Chapter-2:

"A few days later I am transferred to the 3rd squadron as engineer officer and have therefore to bid the first flight good-bye. Steen cannot pull any strings to stop my transfer and so I am now engineer officer of the 3rd squadron. I have barely arrived when the squadron commander leaves the unit and a new one takes his place. Who is he? Flt/Lt. Steen! "

The whole chapter describes Rudel's debut fightings before air attack of Leningrad,i.e, Sep 1941. And for many infos shows that Steen was appointed as the commander of III/StG.2 in Aug.1st 1941.

Here is another info proves that:

Soon after Easter he joined I/StG 2 in Greece, only to find that his old reputation had preceded him. Grounded by a biased Kommandeur, he sat out the assault on Crete.Transferred to the Eastern Front, he flew his first operational sorties with 3/StG 2 and was shot down by ground fire, just managing to regain the German lines before force-landing. Under the tutelage of Staffelkapitan Ernst-Siegfried Steen, who later earned a posthumous Ritterkreuz, he gained experience which was later to stand him in good stead. In August Rudel was transferred to III/StG 2, to find that Steen had just been appointed Kommandeur.

So, i'm totally out of clear. Which one is true? who can tell the details of his carrer in StG.2?
Thanx alot!