p+U reaction

Dear FLUKA users
I am traying calculate the total number of neutron produced during
reaction p+U-238 (see attachment) (1.22GeV)
The experimental result[1] equal to 38.8+-5%,
the calculation result egual to 44.0
What am I doing badly?

Kind regards
Andrzej

[1] L. Pienkowski,* F. Goldenbaum, D. Hilscher,â? and U. Jahnke, Neutron
multiplicity distributions for 1.94 to 5 GeV/c proton-, antiproton-,
pion-, kaon-,and deuteron-induced spallation reactions on thin and thick
targets.PHYSICAL REVIEW C VOLUME 56, NUMBER 4 OCTOBER 1997