In 1971, another significant change came with the introduction of a body of elders. The body was to rotate individual responsibilities annually, with the Watchtower 1971 November 15 p.685 and p.691 noting that the Early Christian elder bodies "likely rotated." It is common for Watchtower to introduce a comment that has no solid basis with phrases such as "of course" and it is "likely".
"Of course, in such a congregational presbytery or “body [assembly] of older men” there would have to be a chairman, to direct the order of meetings of the “body of older men.” Just how a member was appointed as the chairman is not shown in the Scriptures. It would not be a permanent chairmanship, but likely it was ternporary, for a period of time, and was rotated among all the coequal members of the “body of elders.” Watchtower 1971 Nov 15 p.691
Four years later, the 1975 Yearbook praised the success of this new arrangement as "God's doing."
"Reflecting on the new congregational arrangement providing for elders and ministerial servants, Roger Morgan was moved to say: "This is God's doing." Doubtless others will agree, since they may have considered the resulting benefits. The first shifting of responsibilities began in September 1972, and by October 1 the arrangement of things in most congregations had been adjusted. ... The Watchtower remarked: "Truly, Jehovah is bringing his congregated people into an organizational condition in which they will be able to ride out Armageddon into God's new order under divine rulership."" Yearbook 1975 p.250
However, rotation did not work effectively and it was done away with in the 1983 Organized to Accomplish You Ministry, page 41.
"The elders do not serve in these positions on a rotational basis." Organized to Accomplish You Ministry p.41
How can a procedure be God's doing with Biblical backing if within a few years it required removal? Watchtower justifies this as refinement.
Watchtower 2014 Jan 15 p.15
Back and forth changes to organisational structure are not refinements from God, they are simply different management decisions, as occur in any corporation. If Jehovah really had directed the arrangement to be in line with the early Christian example, he would have gotten it right the first time around.
https://www.jwfacts.com/watchtower/elders.php