Destination address does not receive all of sent Ether. Some wei was lost when I sent small amount of ether

Question

When I sent 1000000000 wei, the destination address received only 999997440. 2560 wei was lost. Can you tell me how I can fix it? Where did 2560 wei disappear to?

(Balance before Send)
Source: 211109215254170802845
Destination: 124492759039157024777

(Balance after Send)
Source: 211109110253170802845 (-105001000000000) <= As expected. It includes value and fee.
Destination: 124492759040157024777 (+999997440) <= Not as expected. I expected 1000000000 since I sent 1000000000. 2560 wei was lost.

https://ropsten.etherscan.io/tx/0x70bc34dd4a845f07d49edb60b951df8ca926ef9f357c191f981e96276471168c

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Update 1

I sent 0.1 Ether. Then the destination address received 0.1 Ether as expected. Seems it might be related to how much ether I send.

Answer 1

I'm not sure why you think that 2560 Wei is missing:

124492759040157024777 - 124492759039157024777 = 1000000000 exactly, so everything is as expected.

You can do BigNumber calculations here: https://defuse.ca/big-number-calculator.htm