I personally do not like 4 week PCT, though it is very common and has been around for a long time.
Working side by side with endo's, I learned that natural HPTA can take anywhere from 2-12months to fully return in each user. Of course using certain compounds definitely expedites this..
HCG of course being suppressive, however for the first week or two of PCT (long term PCT) it is advantageous that it spikes LH and FSH, and it also targets testicular atrophy. Think of it like jump starting a car..then of course you must consider that it is suppressive and so therefore your true PCT needs to be run for longer terms after administering it. Think of PCT as a "process".
So even a basic Clomid and Nolva PCT for say 2-3 months duration, AFTER ,even hypothetically doing say 2-3 shots of hcg @ 500mgs E3d for the first 2 weeks, is by far superior to a basic PCT protocol of only 4 weeks.
The proof, if you must have it, is if you look at prescribed HRT/TRT, many of these doctors are now using Clomid therapy only. 25-50mgs ED for 3-6 month periods to try and turn back on the users HPTA. Remember clomid is NOT suppressive.
So running it longer, is always advantageous. It is far better to risk sides of clomid (acne and mood swings being most common) then being deficient in testosterone and losing muscle, gaining bodyfat, losing strength, and psychological disturbances such as mood swings and depression not to mention low testosterone is commonly attributed to lower libido and potentially partial impotence, etc..
Remember, Anti-E's like clomid also show increases in Free Testosterone levels as well as a benefit.
Commonly even a patient who is hypogonadal, say 240 nanos or below, can gain 2-300 nanos on their total testosterone levels using only 25mgs ED over a few month period.
If you are going to bridge or just go back on say 60 days later then much of PCT is done in vain. I would argue a "bridge" at low dosage would be far superior. 100mgs of Cyp E4d in most users 18-50 years old will put the average user in a frame of 700-1200 nanos (on average).
^^My 2cents^^