Might have found part of the answer myself readring the following:
https://prologue.blogs.archives.gov/...-record-series
and
https://www.govinfo.gov/content/pkg/...-sec578-61.xml
On the basis of this, my interpretation of Kellstrom's card is that
(a) Award of Air Medal according to General Order #301, 2 Sep 44
(b) Award of 1 additional Air Medal according to G.O. #421, 13 Oct 44
(c) Award of 1 additional Air Medal according to G.O. #570, 1 Dec 44
I would still be interested, if anyone is able to confirm the reading.
Mikkel