Results from crysfire:


20   47.43   1881.291  1.00 C KOHLv7.01b    13.9580  18.3657   7.4379
90.000  99.365  90.000   52.7237   29.6471  185.6753     .0000   32.2007     
20   47.3    1880.16   1.00 C ITO12/log     13.9545  18.3637   7.4362
90.000  99.368  90.000   52.751    29.654   185.763      .000    32.227       
20   24.3    1880.929  1.00 P DICVOL91/log   16.8463  18.3668   7.4367
90.000 125.171  90.000   52.733    29.644   270.602      .000   137.617
   
20   23.4    1880.722  1.00 P DICVOL91/log   13.9582  18.3637   7.4365
90.000  99.370  90.000   52.724    29.654   185.750      .000    32.224      


The cell appears to be:


a=13.958
b=18.3657
c=7.4379
alpha=90
beta=99.635
gamma=90.00


The alternative 125.171 degr solution by DICVOL and TREOR can be easily
converted to the other cell by


a'=-a-c
b'=-b
c'=-c


I used default runs of crysfire, but don't understand the so different M20
for practically the same solution ...