Yes, the durations of hours 14–21 are determined by the sets of three layers of electronic music. The lowest and slowest layers are also the longest, the highest and fastest at are the shortest. You can see how this works in the form diagram Stockhausen drew for COSMIC PULSES ("The form scheme" about a third of the way down this page:
<http://www.sonoloco.com/rev/stockhausen/91.html>;
The upward slope at the beginning, which shows the entrance of the layers, is more gradual than the one at the end, showing their exits. The durations for each set of three layers can be read directly from this diagram.

But there's one exception: Layer 24 which should end at minute 24 runs through til the end of CP. I guess Stockhausen made this to "peg" the music in the last two minutes when only the layers 3 to 1 can be heard.
By the way: Jerry, your link to the form schem of CP doesn't work. Here's another one: http://www.stockhausen.org/cosmic_pulses_prog.pdf

Here is another question for you (Jerry), as your knowledge-base seems pretty deep on KS's work, (my experience is mostly visceral) .. I've heard/read that phonetics is an area where Stockhausen was especially strong, so for the vocal ones of 14-21 .. would he just eye certain words, phrases and see there maximum musical potential first and how it would work best in the grand scheme of pieces like these, as opposed to merely picking them for what they mean or represent. Leaving those poetic or literary aspects more ambiguous or abstract, a lower tier consideration.

Thank you, Christian, for supplying the link I was looking for, but could not find. For what it's worth, the other one had a typo in it: a final semicolon, which renders the immediately preceding closing angle-bracket a part of the URL, instead of a delimiter. This appears to be generated by the text editor used on this site, and I imagine I should have used the "code" function from the edit bar, instead of trying to type these in by hand.

James, your question is a very good one. Stockhausen studied phonetics and communications theory with Meyer-Eppler at Bonn University in the 1950s, and this had a lasting influence on his music. However, in the four KLANG vocal solos, I don't see much evidence that Stockhausen was interested in their phonetic content, though a phonetic analysis might be an interesting line of inquiry. Rudolf Frisius analyses the texts of these pieces in considerable detail in volume 3 of his book on Stockhausen, but only from the point of view of syllable counts, line lengths, key words, and so on.

There is one exception, in the sketch for JERUSEM (reproduced on the covers of the CD and the score), where Stockhausen has analysed the vowels and some f the consonants of the very short text. Frisius does not mention this, probably because, like myself, he could find no application in the composition itself. Stockhausen's sketches are full of things like this: ideas are tried out but then rejected because they did not lead to anything useful.

The settings of the texts, by the way, are very schematic. If you have not seen the scores, then you may find it useful to know that, for the most part, each syllable of the text is set melismatically, with a different number of notes per syllable. These notes are notated as grace notes, "not sung fast, but with rubato." The numbers of notes per group are often presented in ascending or descending order. For example, the first line of text in JERUSEM has the syllables set to 7, 6, 5, 4, 3, 2, and 1 notes, followed by a concluding flourish of 3, 2, and 1, with the final, single note (D-sharp) repeated with octave grace notes. It appears that this schema took precedence over the text structure, because Stockhausen repeats one syllable (the "Schu-" in "Schulen"), and the title word "Jerusem" is added at the end of the line, which originally had only eight syllables. Similarly, this text is so short that Stockhausen found it necessary to repeat it four times (with some further internal repetitions). In short, it does not look as if the text had very much influence over the musical setting, but instead was repeatedly adapted to the needs of the melodic construction.

HAVONA's much more elaborate text displays similar internal repetitions in order to fit a melodic phrase structure that often does not conform to it, and Frisius sees the steady increase of group sizes in the opening as text-painting of the "Schritt für Schrtitt" progress described in the text. But lest I leave the impression that the melismas always either grow or shrink, the fifteenth phase of HAVONA, for example, at the words "ORVONTON über EDENTIA bis zu HAVONA" has melismas with 1, 8, 2, 7, 3, 6, 4, and 5 notes, and the sparse twenty-first phase has 4, 2, 1, and 3 notes, before a concluding, single "central tone" with many repetitions. Even the phrase "streben Schritt für Schritt," when it comes back for the third time at phase 19, is set with several syllables per note group, in clusters of 6, 1, 5, 2, 4, 3 before its final, repeated central tone of E.

Stockhausen once claimed that he wasn't a libretto specialist, or a professional writer, even alluding to that fact that he was naive in this regard .. but said that what he does ultimately "works" .. so thinking of that made me ask. He is known to have considerable skill with phonetics, and musical considerations always seemed of paramount importance to him over all else. So I guess that was what he was meaning by "it works". Another thing too, is that he gets considerable criticism from high profile peers, others in the field etc. for the text aspects of his pieces, especially the later works like SIRIUS, LICHT and KLANG. Not so much the musical use of them, but their content. Anyone have thoughts on this ..

Sounds like a new topic to me, so I have created the thread "Stockhausen as librettist".

Well, it seems Jerry has pretty much covered KLANG 14-21, but here's my blog post overview anyways. I guess at the very least it's handy in that it has a timetable for each of the 24-odd Moments in each of these works, which kind of shows the "shape" of each of the 24 "verses" in the pieces.

http://stockhausenspace.blogspot.com/2015/03/klang-hours-14-21-overview.html