I didn't read the article word for word, but from what I saw, he appears to be correct. I wrote a similar article several years ago. In fact, this one looks remarkably similar to mine in terms of content, although less well-written, if I do say so myself
Esters directly affect the rate of estrogen conversion, protein synthesis, and peak plasma levels.
The latter is common sense, and different release rates will result in different peak levels of the drug in the bloodstream.
However, fewer people are aware of an ester's abilities to influence estrogen conversion and protein synthesis. Literally every single study since the 1930's onward (there have been dozens of them) have shown that longer esters increase protein synthesis to greater degree than short esters, per mg.
Longer esters also increase the rate of estrogen conversion, which is why they tend to result in more water retention. In theory, this increased rate of estrogen conversion could also result in a greater degree of HPTA suppression, as estrogen itself is suppressive of testosterone production.
However, whether or not short esters increase peak plasma levels (blood levels) to a greater degree than longer esters will depend on both the frequency and number of injections administered. In only one injection is administered, shorter esters will result in higher blood levels due to their more rapid release rate, but this faster release rate is an disadvantage when comparing blood levels after multiple injections have been administered.
When longer esters are injected at an equivalent dosage over several weeks, their delayed release rate will allow blood levels of the drug to accumulate--or "build" on each other--culminating in a higher peak blood level. In contrast, short esters will clear the system within a few days to a week, so blood levels will never rise higher than they do within the first week. Very little "building" takes place. With a long ester like test undecanoate taking up to 6 weeks to fully release into the bloodstream, as many as 6 weeks of injections can build in the system at once, resulting in super high blood levels by the 6 week mark.
What I find odd is the large number of people still claiming that esters have no effect on the activity of a steroid. Now, if all these esters provided visually identical effects, I could understand why someone might think this, but how can someone deny that esters have no effect on the body when we have visual "proof" right in front of our eyes? Obviously, if we get a different effect when attaching a different ester to the same drug, common sense tells us that the ester has something to do with it. As noted above, clinical evidence is also available, in which the different testosterone esters have been demonstrated to increase protein synthesis to different degrees.