Sure, nothing wrong with simplifying things, but "Both ends are sending sackOK. This will enable Selective Acknowledgement. It switches the sequence numbers and

Sure, nothing wrong with simplifying things, but "Both ends are sending sackOK. This will enable Selective Acknowledgement. It switches the sequence numbers and acknowledgment number to use byte range instead of TCP segment numbers." is just flat-out wrong, and in particular suggests that "numbered segments" is not a simplification but an actual fact about how the thing works.