With dynamic fees it was asking for 3+ mBTC as the minimum and manually I can set it at 0.3 mBTC at minumum. I check prediction bitcoin fees website and they say cheapest fee is 0.005 mBTC. How come there is such huge difference?
For 5mbtc per kilobyte (0.005btc/KB) it'll get confirmed within the next block. The 0.003btc per kilobyte is considered to be the amount currently to get your transaction confirmed in 25blocks (about 4-5 hours). As every block is found on average every 9-10 minutes.