First of all, I deliberately found the English version of the original work, because the author's translation is somewhat flattering.
My premise is:
The original income of B is 1.3, and the cost is 0.85 *1.015 = 0.86275.
According to the assumptions in the book:
"27% divorced from the asset value" means that he has lost part of the asset value, and the absolute income is about 27%.
Then the income becomes 1.3-0.27= 1.03, and the yield is1.03 ÷ 0.86275 =1. Revenue-cost ratio 19%, the same as A.
Traceability of loss measuring instrument;
The author mentioned that "a closed investor can meet the market discount of 12, and then his return will drop to the level of an open investor".
This means that from the perspective of a closed-end investor (referring to an open-end investor with comparative terms), he can (possibly) allow a loss of up to 12 point on the return price (discount, based on asset value).
Then the above assumption says there is a loss of 27%. We attribute this to the recovery stage and subtract 27% from the asset value, that is, 0.85-( 1-27%)= 12% of the quoted principal (excluding commission).
At this point, all parameters have been calculated.
Summary:
Graham's expression is somewhat ambiguous, and the management mode of modern funds has changed greatly, so this is a kind of mental training, which can accurately calculate the profit and loss of modern funds and avoid misunderstanding.