Most of the confusion in cycle lengths with peptides comes from the uncertainty in long term sides. Any GH cycle, whether it be peptides or HGH, needs to be in the 6 month range for best results due to the nature of the Growth Hormone; however, because peptides ramp up your bodys own production via the hypothalamus or pituitary, depending on the peptide, it is best to run peptides for 6-8 months to see a desired effect of increased HGH. 6 months on any one peptide is just not a good idea, my guess is because it is just too long on the same receptor--either way, not completely sure.
So much is still unknown with these peptides so I'd say just use caution and mix it up after a few months...