80 and 200 point rule

After reading the rule book many many times I’m still confused on the significance of having an 80 point rule and a 200 point rule.

What is the significance of having both? Wouldn’t just the 200 point rule be sufficient?

I’m sure I’m just missing something in the explanation. Perhaps someone here can help.

Thanks

The short version is that 80 points is for alternation, 200 points for equalization. The wording of 29E5 a and b is somewhat confusing; you have to refer back to earlier paragraphs to see exactly what they mean by “due color.” There is a tiny difference between “equalization” and “receive one color two or more times more than the other color,” but it’s going to come up only in very long tournaments.

Another area where 80 and 200 are often used is to use 200 for pairing transposition limits within the halves of a score group while only using 80 for interchange limits between the top and bottom halves of a score group.

Examples:

Score group with 2000 and 1850 due black, 1900 and 1700 due white. The 150 point transposition of 1850 and 1700 allows colors to work. It is actually considered a 100 point transposition of 1900 and 2000. Either way it is within the 200 point limit and the transpostion is good.
1700-2000
1900-1850

Score group with 2000 and 1850 due black, 1900 and 1600 due white. The 100 point transposition of 1900 and 2000 allow colors to work.
1600-2000
1900-1850

Score group with 2150 and 1850 due black, 1900 and 1600 due white. Transposing 2150 and and 1900 is 250, which is too much. Transposing 1850 and 1600 is 250, which is too much. You can then look at interchanging 1850 and 1900, which is within the 80 point limit.
1900-2150
1600-1850

I don’t believe there is any justification for this distinction in the rules now, though it is, of course, a reasonable pairing variation. Both the 80- and 200-point rules refer to “transpostions and interchanges.” The only distinction made between them is that a transposition should always be preferred to an interchange if both of them are within the rating limit. This is, however, a highly technical point, which goes well beyond the original question.