@alessandro : " I use 10gr/lt of dichromate and 10ml/lt acid and use 3min standard bleaching time." Wow that's high concentration from the recipes I have seen. When I researched this last year I got the most useful info from 'mrred' who posts here, from his blog - My Fim Stuff - on blogspot, specifically using Foma classic and other films and my original source for the Iron Out info. He used 6gr/ltr dichromate. I use the sodium bisulphate, 55gr/ltr, acid substitute as it is easier for me to obtain.
I have been paranoid about over bleaching. I found a thread on Apug last year fom someone quoting from a book by Haist about reversal development. I can't find the thread now maybe it is archived, but have copied the content so if you want that would be happy to email it to you. Quoting from the book he said that a dichromate bleach, 0.5% K dichromate & .5% H2SO4, should be done within one minute and time should not exceed 3 minutes.