TOKYO, Dec 27 (Reuters) - Apple Inc's (AAPL.O) Japan unit is being charged 13 billion yen ($98 million) in additional taxes for bulk sales of iPhones and other Apple devices to foreign tourists that were incorrectly exempted from the consumption tax, the Nikkei newspaper said.Citing unidentified sources, the Nikkei reported on Tuesday that bulk purchases of iPhones by foreign shoppers were discovered at some Apple stores with at least one transaction involving an individual buying hundreds of handsets at once.Apple Japan is believed to have filed an amended tax return, according to Nikkei.In response to a Reuters' request for comment, the company only said in an emailed message that tax-exempt purchases were currently unavailable at its stores.The iPhone maker's Chief Executive Officer Tim Cook visited Japan earlier this month and announced that the company had invested more than $100 billion in its Japanese supply network over the last five years."