The problem with whoever wrote CAP413 and other phraseology manuals is that the phonetic pronunciation is not phonetic.
I don't know what accent they were trying to phoneticise, but WUN, could be meant to rhyme with either (an RP accent) "sun" or the vowel sound could be "oo" as in book, depending whether the author was from north or south of Watford Gap. Similarly, FOWER might rhyme with "hour" or "forward" (without the final d), which I reckon is closer to what was intended.
NB I have had to make a few assumptions about how everyone out there pronounces the words I have used as examples.
As a lot of our international brethren have to learn English, it would not be too hard for all of us to learn a few proper linguistic Phonetic alphabet symbols and have all words which have prescribed pronunciation properly phoneticised.