e.g. the size of odoo/odoo is given on odoo/odoo as 12152591, when dumped into a .csv file from your GitHub Search it's given as 12150000. So in general, your query is correct.

However, on the query results page of your GitHub Search it displays Size: 11.59 MB.

It seems, you have to go up on your query result page like this KB->MB, MB->GB etc., i.e. three orders of magnitude for each size for each project.