Fishy’s 40 bagger, page-187

The reclaim process can be long & complicated, if wrong or incomplete information is submitted to tax authorities the reclaim is denied.

The company doesn't have to figure out 10%, they have to work out which items they're allowed to reclaim back, some countries have time limits on how long companies have got to initiate a reclaim or there is a certain limit that needs to be reached first before you can reclaim. There are different rules for different countries, so it's not clear-cut & simple at all. Then there are forms to fill out, it can take weeks or months to complete the entire process.