I was trying to confirm the "cold storage spending" feature and change return process with a simple test. It did not work as I expected it to. Hopefully someone can tell me what I did wrong.
I had an address with only 0.25 mBTC in it. I used the Mycelium Cold Storage feature to spend from it. I scanned the private key and had it spend 0.14999 mBTC to one of my Mycelium addresses, and a miner's fee of 0.1 mBTC. I was expecting to see the remaining 0.00000001 mBTC returned as change to the same cold storage address.
Instead, what happened was that the 0.14999 mBTC went to my Mycelium address, but the miner got 0.00010001 mBTC. So, was that new amount an adjusted miner's fee? Or was the miner's fee still 0.1 mBTC, but the change of 0.00000001 mBTC go to the miner?
Or does this have something to do with the small dust levels I'm playing with? If I was to spend a partial amount from my cold storage, how can I trust that the change will be returned to my paper wallet?
Thanks
There is a minimum limit for standard outputs, 5460 satoshis. if such an output is part of a transaction it is considered nonstandard and will by default not be relayed. (and thus not mined)
Mycelium makes sure that your transactions have a chance of working and does not produce change outputs that are smaller than this limit, so the rest <= 5460 satoshis is included in the mining fee.
the reason is, on average such outputs can not be spent economically because they make the transaction bigger. some more background info is here:
https://www.reddit.com/r/Bitcoin/comments/1drocs/to_everyone_wringing_their_hands_over_the_recent/