1. it should read ...type of WEIGHING not weighTing (see link
http://www.wordmagicsoft.com/dictionary/es-en/pesada.php)
2. It seems to be the correct answer but it is unusual because the next item in the list is 'factor gravimetrico' - or gravimetric factor, which means measurement of the mass (or weight in lay terms).....therefore it seems to me that the measurement of this variable (the mass or weight) is performed or at least considered twice.
May I suggest the 'pesada' means 'weighting' as offered by Alistair BUT not weighting as in mass, but however weighting as in biasing, (e.g. "the golf tournament was weighted (handicapped is more typical in this example) so that players of all different abilities could play together")
So ----> conversion to another type of scale.
The translation workplace 
