According to Section 5-36 of the manual, on a meridional line the latitude of the closing distance will be distributed along the measurement of each course in proportion to its own difference in latitude, and then each temporary stake will be set over to the east or to the west for the departure of the closing distance in proportion to the total distance from the starting point.

In other words, on an irregular line, adjustments in the direction of the line whether latitudinal or meridional are done just like single-proportion, while adjustments perpendicular to the direction of the line are done according to the Bowdich Method, or more commonly referred as the Compass Rule.

So, in this problem, we would distribute the latitude of the closing error using the single proportionate ratio.

The latitude of the closing error is to the sum of the record latitudes as the adjustment to each course's latitude is to the accumulated record latitude of that course, or A1 is to A as B1 is to B in the drawing.