Dominik wrote:

As for ISO standards becoming freely available, I doubt that that will happen any time soon.  

Note that the ISO standard document contains much more than just tables of transliterations . There are three pages of rules and recommendations which need to be known to apply the standard.  

For example this rule about interpreting anusvara and this recommendation about word breaks which also requires interpretation of the original script. The standard even says about the recommendation " This will require a good knowledge of the language in question".  But Rule 3a also requires a good knowledge of the language in question.  

Should a transliteration standard require a language expert to apply it?  Or should it be such that a typist with a knowledge of the script be able to apply it?

Rule 3a also means that if you produced a diplomatic transliteration of a manuscript (leaving anusvara as anusvara)  you would be deviating from the ISO standard.
 
From the ISO  standard document.
. . .

8.1 Special requirements

. . .

Rule 3.

. . .

a) In modern vernaculars, anusvara before a stop or class nasal shall be transliterated as the corresponding class nasal; in other languages, anusvara before a stop or class nasal shall be transliterated as the corresponding class nasal unless it arises from sandhi (euphonic combination) of final m with that consonant.


EXAMPLE 1 Sanskrit संग is transliterated as saṁga when it represents the noun formed from sam + root gam, but as saṅga when it represents the noun derived from the root sañj.

8.2 Recommendations

Where word boundaries are not shown in the original text (as happens commonly in Sanskrit) and a word ends in a consonant, the transliteration should show word division by a space; but when phonological processes result in two words sharing a common vowel, no attempt should be made to separate them. This will require a good knowledge of the language in question.

 
Harry Spier