Can we complete quran by reading from book and then from device

I read quran and mark where I stopped and then continue on my device or sometime from online quran and when reach home again from quran book. By this way am I completing my quran? Because somebody told me if you started from quran book then you should stick with that quran book until you complete the quran or else it doesn't count as you have red the whole quran!! Is that true?