The capitalisation is confusing, but "Mi" means "mebi" - either Mib for mebibits or MiB for mebibytes. The correct term for 1024 * 1024 bits is a Mib, and, 1024 x 1024 x8 bits is a MiB.
That is correct, but it doesn't answer the question whether it's Bytes or bits (which makes an 8x difference).
Given that the reported values don't care about the "m" (which means "milli" -- clearly doesn't make sense for bytes), I don't think we can rely on the casing of the "b" to tell us the answer.
