Quick three of coins question

I bought my xbox and started playing destiny this past Thursday. So its been about 6 days since I created my guardian. I am level 40 with 291 light. I was reading a guide in this subreddit and it said this

"3 of Coins--Xur sells these. 5 for 7 strange coins. Using one before you kill an Ultra or raid boss will give you a chance to drop an exotic weapon or armor piece. It appears to be about a 1/3 chance increase as using 10 coins should net you about 2-3 exotics. Good luck, Guardians!"

Can you really pop 10 of them to get 2-3 exotics on a lvl 41 strike? Or have they changed that?