Jean, you are writing fast than I can read and answer...
Today I found another interesting document, a thesis of 119 pages about the German POW system 1939 – 1945:
http://ubm.opus.hbz-nrw.de/volltexte/2009/1884
On afirst look it is quiet abstract but contains also information concerning escapes and some statistic charts:
Jean, your dad was one of the first American prisoners of war in this area: on 1st October 1944, there were no (0) Americans in the camps in the military district VI of about 40,000 in other districts or in camps run by the German Air Force (Stalag Luft), but more than 106,000 of about 922,000 French soldiers! The young student Neifer wasn’t on the hill anymore when the first American arrived there as he served as acolyte in the abbey only until 1944 as he told me. And these numbers also show that there were many more French than American prisoners in the area... The thesis also explains that escaped prisoners of war were a big problem for the German authorities. Even if only 2 per cent of the prisoners escaped (or tried to), there would have been about 80,000 escaped enemy soldiers in Germany over the years!
This time I will not translate the complete text 
but one sentence:
Compared with the overall number only few prisoners of war in German custody have made an attempt to escape in WWII and scarcely anybody really reached his home or a safe country after a successful escape.
I'll have to read the whole text, that will give me a good background for further research 
Don't let the hurricane blow you away!
Christoph