Debug OSC shipping calculation - use of weight attribute

This site has some products which use the base product screen to record the weight (for shipping calculation and for display) and other products available in a variety of sizes that use a weights attribute to show the range of different sizes - in this case the base product weight (and price) is zero and the shipping calculation uses the weight attributes (which also shows the price variance). The weight attributes had to be set so that the calculation always had the same units (grams I think) - even though the sizes could displayed could be eitehr grams or Kg. Recently someone updated all the products and unfortunately changed all the weight attributes, so now the shpping calculation doesn't get the right information for some products. I ONLY need someone who can inspect the database and the shipping calculation, and who can tell us how to correctly input the weight attributes again (it might be something like 5kg=5,000grams). Everything was working until the attributes were changed, so no coding should be neccessary.