Exchange fee != wallet to wallet fee?
What you want to say? That exchange fee is only 10 drops? Where?
No, I want to say that exchange takes higher fees, though you have not described situation how you got bigger drop, it might help to shed a light.
Sent from Bitstamp wallet to Poloniex wallet
Sent 3 times, 50, 1400 and 2000 XRP, always the same fee