Not by any means the first time in history that private finance has been a major factor in the use of a Swiss orchestra by a foreign company, Bryn. Why do you think there were so many Ansermet/Suisse Romande recordings made by British Decca?
I wonder whether, in this case, the recordings didn't come first, and the search for a record company to issue them came somewhat later? The recording dates for symphonies 1 to 4 are 11/2004, 6/2005, 5/2006 and 9/2007 respectively.
Now that I look, Oehms seem to be continuing a Beethoven symphonies survey, but for 3 to 6 are using De Billy and the RSO Wien.