There is a whole insane debate on this issue here
So the break down is this:
1000 kilobytes mathematically is 2^10 bytes =1024 bytes. This is working off the fact that a byte is technically 2 nibbles = 8 bits
1mb has always been 2^20 = 1024 kilobytes
1gb has always been 2^30 = 1024 megabytes
1tb has always been 2^40 = 1024 gigabytes
Hardware manufacturers and software developers still refer the math. Everyone else refers to a generic sense of rounding of the few extra bits. So to differentiate the match from the marketing...newer terms have been implemented... giby..mebi...etc to refer to the math..
When using something like robocopy, it's based on programming and exactness rather than a rounding off nature of numbers. so you get 1024.1..etc.
*if the post above has answered the question, please mark the topic as solved.
**All "answers" and responses are offered "as is" and my opinion. There is no implied support or guarantee by the ITProTV team.