Did i understand you right, that "print 1762.09-(1357.49+404.60)" in the python console gives "-2.27373675443e-13" as answer on your openerp server? with the same python version your openerp server is running on?
Did i understand you right, that "print 1762.09- (1357.49+ 404.60) " in the python console gives "-2.27373675443 e-13" as answer on your openerp server? with the same python version your openerp server is running on?