It isn't. The problem with a vernacular pronunciation guide is that you need to think about ambiguity. /a-sim-TO-ti-klee/ is a much better syllable break, but

It isn't. The problem with a vernacular pronunciation guide is that you need to think about ambiguity. /a-sim-TO-ti-klee/ is a much better syllable break, but /TO/ is likely to be mispronounced /'tu:/. And /TOH/ could be interpreted as /'toʊ/. So /TOT/ splits the difference between syllable break and pronunciation for (imho) maximum clarity.