i can understand working your way UP in dosage if you've never tried t3 and are trying to establish your 'comfort zone' with this compound. once you've determined your dose, you can simply start with that dose and get the full benefits of t3 for the duration of the cycle vs. for 60-75% of the cycle. i see no reason for the tapering at the end and it really makes no sense at all.
now, i'm not sure why you'd want to even do that much t3 either. imho, for most guys 25-50mcg ed, along with an
aas cycle, would work really nicely. and you'd have very minimal thyroid shutdown at that. why 125 and 150mcg? at those doses, you will be burning a lot muscle, not to mention how shitty tired you'd feel, and how weak you will start to feel, to boot. and that certainly not going to help you work out hard and heavy.
in a nutshell, t3 is some potent stuff. if you're gonna use, do some research and get a variety of 'opinions' before you start using it. but whatever you do, don't take those high doses. for MOST guys, those doses are overkill and coutner-productive. good luck