For info, I re-checked the dose coefficients: originally I had given a detailed look to the neutron ones because they were from an American Standard which was unknown to me and as I replied to you the differences were quite small although the conversion coefficients implemented in FLUKA have a much more refined granularity. I trusted that the photon ones were close to the ones in FLUKA since they were from an ICRP publication.
Well, I went back to the quoted ICRP publication, in particular to table 3 at page 16: the coefficients in the ICRP publication were given as (photons/cm2 s)/(mrem/h) so then ones in the article should be their inverse divided by 100 for the conversion rem->Sv. The coefficients in the article, though, are a factor 10 less than what should be!
In this case this has a small effect since the dose due to photons is much smaller than the one due to neutrons at least laterally to the tank. I have tried using the coefficients in the article in a routine and the difference with respect to the FLUKA built-in scoring is around 20% laterally outside the tank.
Please let me know if you have further questions.
Cheers,
Davide