We’re still better off writing our own, that way we can cover other situations we are likely to come across that aren’t covered.
Additionally, what if we want a ranked ballot in an approval election to translate to an approval for everyone ranked above RON as was mentioned here? I don’t know which method people like more, that one or the one covered in example 16, but by writing our own we have more control.
The booklet is much better than nothing, but this proposed amendment would be a lot better off with our own ones since we’re interpreting invalid votes into two different voting systems, neither of which are the one that that booklet contains guidelines specifically for.