if anna's theory about the syncopation is correct surely he would not have included cuban breaks either.

my own theory is as follows. the first step of the spiral turn must end fwd with reasonable cearance from the other foot. if this were not acheived it would not be possibe to make a clean turn to a spiral cross as the feet would clash. the cha-cha-chasse on the other hand could be taken towards the R side of the man but would need to be fairly compact to maintain contact - and then in making those steps compact the spiral turn would be compromised as above.