The indicator new_statement, don't work anymore and for now I use a variable that is set at the last historic value, ie 
myvar = hist_1_pl, 
and I use a condition mayvar not =hist_1_pl to read the new value.
This gives problems when hist_1_pl=hist_2_pl. 
I woundering if somone got a better solution I think I had one before using time but I don't remember.