Explain your vote, thanks.
My vote is for 3 x 360 degrees.
ABOK #36 shows a Round Turn that includes about 360 degrees.
ABOK #37 shows a Round Turn plus an Elbow as being about 540 degrees.
ABOK #40 shows a Single Turn as being about 180 degrees.
ABOK #42 shows Two Round Turns that include about 2 x 360 degrees, and there are 180 degrees that are implied.
According to what I've seen, there is only one diagram that is causing this confusion that a Round Turn is 540 degrees (it's not). The diagram is ABOK #41 (or any diagram mimicking that). In that diagram, the Round Turn is actually 360 degrees, and there is an implied 180 degrees turn.
In every other instance of a Round Turn, it clearly makes no sense to define a Round Turn as 540 degrees. As just a few examples, the definition of 540 degrees clearly breaks down for the following:
-Two Round Turns (ABOK #42)
-Three Round Turns, and so on
-ABOK #36
-ABOK #37